OFFSET
1,1
MATHEMATICA
a[n_] := 2*n + DivisorSigma[0, n]; Array[a, 100] (* Amiram Eldar, Apr 07 2024 *)
PROG
(PARI) a(n) = 2*n + numdiv(n); \\ Amiram Eldar, Apr 07 2024
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Jun 29 2008
STATUS
approved