OFFSET

1,1

LINKS

Ivan Neretin, Table of n, a(n) for n = 1..10000

MATHEMATICA

mx = 100; Complement[Range[mx], Table[Nest[DivisorSigma[1, #] &, n, 2], {n, mx}]] (* Ivan Neretin, Feb 12 2018 *)

CROSSREFS

KEYWORD

nonn

AUTHOR

Jaroslav Krizek, Jul 17 2009

STATUS

approved