OFFSET
1,2
COMMENTS
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
FORMULA
Sum_{n>=2} 1/a(n) = Sum_{k>=2} (zeta(k)/zeta(2*k) - 1) = 0.848633... (A368250).
MATHEMATICA
Table[n*(n - 1), {n, Select[Range[100], SquareFreeQ]}]
PROG
(PARI) lista(kmax) = forsquarefree(k=1, kmax, print1(k[1]*(k[1]-1), ", "));
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Amiram Eldar, Dec 19 2023
STATUS
approved