OFFSET
1,2
COMMENTS
PROG
(Magma) v:=[m:m in [1..500]| not IsPrime(m)]; [v[k]*(v[k]+1)/2:k in [1..65]]; // Marius A. Burtea, Jul 12 2019
(Magma) [n*(n+1)/2 : n in [1..100] | not IsPrime(n)]; // Vincenzo Librandi, Jul 12 2019
(PARI) apply(x->x*(x+1)/2, select(x->!isprime(x), [1..90])) \\ Michel Marcus, Sep 18 2023
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Jul 10 2019
STATUS
approved