A294086 Numbers k such that k divides the number of planar partitions of k (A000219).

1, 3, 6, 8, 10, 281, 382, 590, 5135, 13897, 31387, 37045, 46199, 85057

Offset

1,2

Comments

a(15) > 10^5. - Seiichi Manyama, Feb 11 2018

Next term, if it exists, is greater than 250000. - Vaclav Kotesovec, Mar 02 2018

Links

Table of n, a(n) for n=1..14.

Eric Weisstein's World of Mathematics, Plane Partition

Example

281 is in the sequence because A000219(281) = 126261896396707768167577329446424334 is divisible by 281.

Mathematica

pp[0] = 1; pp[n_] := pp[n] = (1/n)*Sum[pp[n-k]*DivisorSigma[2, k], {k, 1, n}]; Reap[For[n = 0; k = 1, k < 10^5, k++, If[Divisible[pp[k], k], n++; Print["a(", n, ") = ", k, "  pp(", k, ") = ", pp[k]]; Sow[k]]]][[2, 1]] (* Jean-François Alcover, Feb 11 2018 *)

Crossrefs

Cf. A000219, A051177, A056848.

Sequence in context: A310135 A352341 A124051 * A350159 A308221 A350546

Adjacent sequences: A294083 A294084 A294085 * A294087 A294088 A294089

Keyword

nonn,more

Author

Ilya Gutkovskiy, Feb 09 2018

Extensions

a(14) from Seiichi Manyama, Feb 11 2018

Status

approved