A155713 - OEIS

A155713

Intersection of A154778 and A155716: N = a^2 + 5b^2 = c^2 + 6d^2 for some positive integers a,b,c,d.

49, 70, 105, 145, 150, 166, 196, 214, 225, 241, 249, 280, 294, 321, 406, 409, 420, 441, 454, 505, 580, 600, 601, 609, 630, 664, 681, 694, 721, 726, 745, 769, 784, 841, 856, 870, 886, 889, 900, 934, 945, 964, 996, 1009, 1030, 1041, 1089, 1120, 1126, 1129

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Table of n, a(n) for n=1..50.

PROG

(PARI) isA155713(n, /* optional 2nd arg allows us to get other sequences */c=[6, 5]) = { for(i=1, #c, for(b=1, sqrtint((n-1)\c[i]), issquare(n-c[i]*b^2) & next(2)); return); 1}

for( n=1, 999, isA155713(n) & print1(n", "))

CROSSREFS

Cf. A000404, A154777, A092572, A097268, A154778, A155716, A155717, A155560-A155578.

Sequence in context: A117459 A137558 A316676 * A112074 A112057 A350182

Adjacent sequences: A155710 A155711 A155712 * A155714 A155715 A155716

KEYWORD

easy,nonn

AUTHOR

M. F. Hasler, Jan 25 2009

STATUS

approved