OFFSET
1,2
COMMENTS
All the powers of 3 (A000244) are in the sequence.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..165
MATHEMATICA
s = {1, 2}; k1 = 1; k2 = 2; Do[k3 = (2*n*k2 + (3*n - 9)*k1)/(n + 1); If[Divisible[k3, n], AppendTo[s, n]]; k1 = k2; k2 = k3, {n, 3, 42000}]; s (* Amiram Eldar, Jun 28 2022 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Apr 07 2003
STATUS
approved