OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
MATHEMATICA
r = Range[300]; Complement[Select[r, PrimeQ], DivisorSigma[1, r]] (* Amiram Eldar, Nov 15 2021 *)
PROG
(PARI) for(n=1, 100, if(sum(j=1, n, if(sigma(j)-n, 1-isprime(n), 1))==0, print1(n, ", ")))
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, May 16 2002
STATUS
approved