Displaying 1-10 of 18 results found.
Numbers expressible in more than one way as i^2 + j^2 + k^2, where 1 <= i <= j <= k.
+10
24
27, 33, 38, 41, 51, 54, 57, 59, 62, 66, 69, 74, 75, 77, 81, 83, 86, 89, 90, 94, 98, 99, 101, 102, 105, 107, 108, 110, 113, 114, 117, 118, 121, 122, 123, 125, 126, 129, 131, 132, 134, 137, 138, 139, 141, 146, 147, 149, 150, 152, 153, 154, 155, 158, 161, 162, 164, 165, 166, 170
COMMENTS
a(n) multiplied by (h^2)/(8*m*a^2) is the n-th energy level exhibiting accidental degeneracy, for a quantum mechanical particle of mass m in a cubic box of side length a (h is Planck's constant). - A. Timothy Royappa, Feb 12 2019
MATHEMATICA
okQ[n_]:= Length[Select[PowersRepresentations[n, 3, 2], !MemberQ[#, 0] &]] > 1; (* Jinyuan Wang, Feb 12 2019 *)
PROG
(PARI) is(n)=if(n<27, return(0)); if(n%4==0, return(is(n/4))); my(w); for(i=sqrtint((n-1)\3)+1, sqrtint(n-2), my(t=n-i^2); for(j=sqrtint((t-1)\2)+1, min(sqrtint(t-1), i), if(issquare(t-j^2), w++>1 && return(1)))); 0 \\ Charles R Greathouse IV, Aug 05 2024
CROSSREFS
Cf. A000408, A007692, A008917, A025322, A025323, A025324, A025325, A025326, A025327, A025328, A025329, A025330, A025331, A025332, A025333, A025334, A025335, A025336, A025337, A025338, A025367, A025427.
Numbers that are the sum of 3 nonzero squares in 5 or more ways.
+10
22
194, 206, 209, 230, 266, 269, 281, 297, 306, 314, 321, 326, 329, 341, 342, 350, 354, 369, 374, 381, 386, 389, 398, 401, 402, 413, 414, 419, 425, 426, 434, 437, 441, 446, 449, 450, 458, 459, 461, 470, 474, 482, 486, 489, 491, 494, 497, 506, 509, 513, 521, 525, 530, 531
CROSSREFS
Cf. A024796, A025296, A025322, A025323, A025324, A025325, A025326, A025327, A025328, A025329, A025330, A025331, A025332, A025333, A025334, A025335, A025336, A025337, A025338, A025370, A025427, A343967.
Numbers that are the sum of 3 nonzero squares in 4 or more ways.
+10
21
129, 134, 146, 153, 161, 171, 189, 194, 198, 201, 206, 209, 230, 234, 243, 246, 249, 251, 254, 257, 261, 266, 269, 270, 278, 281, 285, 290, 293, 294, 297, 299, 306, 314, 321, 326, 329, 339, 341, 342, 350, 353, 354, 362, 363, 365, 369, 371, 374, 378, 381, 386, 387, 389
CROSSREFS
Cf. A024796, A025295, A025322, A025323, A025324, A025325, A025326, A025327, A025328, A025329, A025330, A025331, A025332, A025333, A025334, A025335, A025336, A025337, A025338, A025369, A025427, A343968.
Numbers that are the sum of 3 nonzero squares in 6 or more ways.
+10
21
209, 297, 306, 314, 321, 326, 329, 341, 342, 369, 374, 425, 426, 434, 441, 446, 458, 459, 461, 486, 489, 494, 497, 506, 509, 513, 521, 530, 531, 534, 542, 545, 546, 549, 558, 561, 566, 569, 581, 593, 594, 602, 605, 614, 621, 626, 629, 633, 641, 649, 650, 654, 657, 659
CROSSREFS
Cf. A024796, A025297, A025322, A025323, A025324, A025325, A025326, A025327, A025328, A025329, A025330, A025331, A025332, A025333, A025334, A025335, A025336, A025337, A025338, A025371, A025427, A345083.
Numbers that are the sum of 3 nonzero squares in 7 or more ways.
+10
21
341, 369, 374, 446, 461, 486, 494, 506, 509, 521, 545, 549, 566, 569, 581, 594, 614, 621, 626, 629, 641, 654, 666, 677, 686, 689, 701, 710, 726, 729, 731, 734, 749, 761, 770, 774, 789, 794, 797, 801, 806, 809, 810, 818, 821, 825, 833, 846, 849, 854, 857, 866, 869, 881
CROSSREFS
Cf. A024796, A025298, A025322, A025323, A025324, A025325, A025326, A025327, A025328, A025329, A025330, A025331, A025332, A025333, A025334, A025335, A025336, A025337, A025338, A025372, A025427, A345086.
Numbers that are the sum of 3 nonzero squares in 8 or more ways.
+10
21
374, 446, 486, 521, 566, 569, 594, 614, 621, 626, 629, 686, 689, 701, 710, 729, 734, 749, 761, 770, 774, 789, 794, 801, 809, 810, 825, 846, 849, 854, 857, 866, 869, 881, 902, 909, 914, 926, 929, 941, 945, 950, 953, 965, 969, 971, 974, 986, 989, 990, 1001, 1014, 1022
CROSSREFS
Cf. A024796, A025299, A025322, A025323, A025324, A025325, A025326, A025327, A025328, A025329, A025330, A025331, A025332, A025333, A025334, A025335, A025336, A025337, A025338, A025373, A025427, A345087.
Numbers that are the sum of 3 nonzero squares in 9 or more ways.
+10
21
594, 614, 626, 689, 734, 761, 774, 794, 801, 846, 854, 866, 881, 909, 914, 926, 929, 941, 950, 965, 974, 986, 989, 990, 1001, 1025, 1026, 1034, 1041, 1046, 1049, 1062, 1070, 1074, 1089, 1091, 1097, 1106, 1109, 1118, 1121, 1130, 1134, 1139, 1154, 1161, 1166
CROSSREFS
Cf. A024796, A025300, A025322, A025323, A025324, A025325, A025326, A025327, A025328, A025329, A025330, A025331, A025332, A025333, A025334, A025335, A025336, A025337, A025338, A025374, A025427, A345119.
Numbers that are the sum of 3 nonzero squares in 10 or more ways.
+10
21
594, 734, 761, 794, 801, 846, 854, 866, 881, 909, 926, 941, 950, 965, 986, 1001, 1026, 1034, 1041, 1046, 1049, 1089, 1106, 1109, 1121, 1130, 1154, 1161, 1169, 1181, 1190, 1206, 1209, 1214, 1226, 1238, 1265, 1274, 1286, 1301, 1314, 1322, 1326, 1329, 1341
CROSSREFS
Cf. A024796, A025301, A025322, A025323, A025324, A025325, A025326, A025327, A025328, A025329, A025330, A025331, A025332, A025333, A025334, A025335, A025336, A025337, A025338, A025375, A025427, A345121.
Numbers that are the sum of 3 nonzero squares in 3 or more ways.
+10
20
54, 66, 81, 86, 89, 99, 101, 110, 114, 126, 129, 131, 134, 146, 149, 150, 153, 161, 162, 166, 171, 173, 174, 179, 182, 185, 186, 189, 194, 198, 201, 206, 209, 216, 219, 221, 222, 225, 227, 230, 233, 234, 237, 241, 242, 243, 245, 246, 249, 251, 254, 257, 258, 261, 264
CROSSREFS
Cf. A024796, A025294, A025322, A025323, A025324, A025325, A025326, A025327, A025328, A025329, A025330, A025331, A025332, A025333, A025334, A025335, A025336, A025337, A025338, A025368, A025398, A025427.
Numbers that are the sum of 3 nonzero squares in exactly 2 ways.
+10
19
27, 33, 38, 41, 51, 57, 59, 62, 69, 74, 75, 77, 83, 90, 94, 98, 102, 105, 107, 108, 113, 117, 118, 121, 122, 123, 125, 132, 137, 138, 139, 141, 147, 152, 154, 155, 158, 164, 165, 170, 177, 178, 181, 187, 195, 197, 203, 204, 210, 211, 213, 214, 217, 218, 226, 228, 229, 236
MATHEMATICA
okQ[n_]:=Length[Select[PowersRepresentations[n, 3, 2], !MemberQ[ #, 0]&]] ==2; Select[Range[250], okQ] (* Harvey P. Dale, Jul 25 2011 *)
CROSSREFS
Cf. A024796, A025427, A025322, A025323, A025324, A025325, A025326, A025327, A025328, A025329, A025330, A025331, A025332, A025333, A025334, A025335, A025336, A025337, A025338.
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