OFFSET
1,2
COMMENTS
Numbers which appear in A000593.
Possible values for the sum of odd divisors of the positive integers, in increasing order. - Omar E. Pol, Jul 06 2016
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
MAPLE
N:= 10000:# to get all terms <= N
p:= 3:
S:= {1}:
while p < N do
S:= map(s -> seq(s*(p^(e+1)-1)/(p-1), e=0..ilog[p](1+N*(p-1)/s)-1), S);
p:= nextprime(p);
od:
sort(convert(S, list)); # Robert Israel, Jul 06 2016
MATHEMATICA
Union@ Table[Total@ Select[Divisors@ n, OddQ], {n, 200}] (* Michael De Vlieger, Jul 07 2016 *)
PROG
(PARI) list(lim)=lim\=1; my(v=[1]); forprime(p=3, lim\4, my(t, u=v, lm); for(e=1, logint(lim, p), t=(p^(e+1)-1)/(p-1); lm=lim\t; u=concat(u, select(k->k<=lm, v)*t)); v=Set(u)); Set(concat(v, apply(p->p+1, primes([lim\4, lim-1])))) \\ Charles R Greathouse IV, Jul 06 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Timothy L. Tiffin, Jul 06 2016
STATUS
approved