OFFSET

1,2

COMMENTS

A005117 (squarefree numbers) is a subsequence. - Ivan Neretin, Dec 20 2017

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Paolo P. Lava)

EXAMPLE

2 is a term because 1 + 8 = 9 is divisible by 1 + 2 = 3.

208 is a term: The power sums of divisors for k = 0, 1, 2, 3 are as follows: 10, 434, 54970, 10288838, and sigma(1,208) = 434 divides sigma(3,208) = 10288838 = 434*23707.

MATHEMATICA

Select[Range@ 85, Divisible[DivisorSigma[3, #], DivisorSigma[1, #]] &] (* Michael De Vlieger, Aug 01 2017 *)

PROG

(PARI) isA046841(n)=sigma(n, 3)%sigma(n, 1)==0 \\ Michael B. Porter, Apr 07 2010

CROSSREFS

KEYWORD

nonn

AUTHOR

STATUS

approved