OFFSET
1,1
COMMENTS
Most terms are == 2 (mod 6), first term == 4 (mod 6) is a(365) = 13474. - Zak Seidov, Apr 18 2013
First term == 0 (mod 6) may be 296527606374. - Jianing Song, Apr 01 2018
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..2000 from Zak Seidov)
MATHEMATICA
Select[Range[2, 2000, 2], DivisorSigma[1, #] < DivisorSigma[1, # + 1] &] (* Zak Seidov, Apr 18 2013 *)
PROG
(GAP) Filtered([2, 4..2000], n->Sigma(n+1)>Sigma(n)); # Muniru A Asiru, Apr 03 2018
(PARI) is(n) = !(n%2) && sigma(n + 1) > sigma(n); \\ Amiram Eldar, Apr 23 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Feb 08 2002
STATUS
approved