OFFSET
1,2
COMMENTS
For all k <= n, add n if k is squarefree, otherwise add 1. For n = 12, the 8 squarefree numbers less than or equal to 12 are 1, 2, 3, 5, 6, 7, 10, and 11. This means that 4 are not squarefree, which gives a(12) = 12*8 + 4 = 100.
MATHEMATICA
Table[Sum[n^Abs[MoebiusMu[k]], {k, n}], {n, 80}]
PROG
(PARI) a(n) = sum(k=1, n, if (issquarefree(k), n, 1)); \\ Michel Marcus, Jun 26 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Wesley Ivan Hurt, Jun 25 2021
STATUS
approved