OFFSET
1,2
COMMENTS
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..2000
EXAMPLE
MAPLE
N:= 10^6: # to get all terms up to N
A002191:= select(`<=`, {seq(numtheory[sigma](i), i=1..N)}, N):
PROG
(PARI) list(lim) = select(n->n<=lim, Set(vector(lim\=1, n, sigma(n))));
isok(n, lists) = {fordiv (n, d, if (!vecsearch(lists, d), return(0))); return(1); }
lista(nn) = {lists = list(nn); for(n=1, nn, if (isok(n, lists), print1(n, ", ")); ); }
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Marcus, Jun 10 2014
STATUS
approved