A065768 - OEIS

A065768

Intersection of A065764 and A065766.

1, 13, 31, 57, 121, 133, 183, 307, 381, 403, 553, 741, 781, 871, 993, 1093, 1407, 1723, 1729, 1767, 1893, 2257, 2379, 2801, 2863, 3541, 3751, 3783, 3991, 4123, 4557, 4953, 5113, 5403, 5673, 6321, 6897, 6973, 7189, 7581, 8011, 9507, 9517, 9841, 10153

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OFFSET

1,2

COMMENTS

Terms are the sum of the odd divisors (A000593) of the odd squares (A016754), written in ascending order. Subsequence of the odd terms of A274790. - Timothy L. Tiffin, Feb 12 2022

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

MATHEMATICA

f1[p_, e_] := (p^(2*e + 1) - 1)/(p - 1); s1[1] = 1; s1[n_] := Times @@ f1 @@@ FactorInteger[n]; f2[p_, e_] := (p^(2*e + 1) - 1)/(p - 1); f2[2, e_] := (4^(e + 1) - 1)/3; s2[1] = 1; s2[n_] := Times @@ f2 @@@ FactorInteger[n]; seq[max_] := Intersection[Select[Array[s1, max], # < max^2 &], Select[Array[s2, max], # < max^2 &]]; seq[101] (* Amiram Eldar, Aug 24 2024 *)

CROSSREFS

Cf. A000593, A016754, A065764, A065766, A274790.

Sequence in context: A063305 A301622 A166143 * A155820 A242231 A330855

Adjacent sequences: A065765 A065766 A065767 * A065769 A065770 A065771

KEYWORD

nonn

AUTHOR

Labos Elemer, Nov 19 2001

STATUS

approved