A152674 Number of divisors of the numbers that are not squares.

2, 2, 2, 4, 2, 4, 4, 2, 6, 2, 4, 4, 2, 6, 2, 6, 4, 4, 2, 8, 4, 4, 6, 2, 8, 2, 6, 4, 4, 4, 2, 4, 4, 8, 2, 8, 2, 6, 6, 4, 2, 10, 6, 4, 6, 2, 8, 4, 8, 4, 4, 2, 12, 2, 4, 6, 4, 8, 2, 6, 4, 8, 2, 12, 2, 4, 6, 6, 4, 8, 2, 10, 4, 2, 12, 4, 4, 4, 8, 2, 12, 4, 6, 4, 4, 4, 12, 2, 6, 6, 2, 8, 2, 8

Offset

1,1

Comments

Even members of A000005.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

a(n) = A000005(A000037(n)).

a(n) = 2*A095686(n). - Amiram Eldar, Dec 02 2023

Mathematica

Select[DivisorSigma[0, Range[100]], EvenQ] (* Amiram Eldar, Dec 02 2023 *)

Prog

(PARI) lista(kmax) = for(k = 1, kmax, if(!issquare(k), print1(numdiv(k), ", "))); \\ Amiram Eldar, Dec 02 2023

Crossrefs

Cf. A000005, A000037, A095686.

Sequence in context: A161841 A335901 A366438 * A072056 A356831 A066012

Adjacent sequences: A152671 A152672 A152673 * A152675 A152676 A152677

Keyword

easy,nonn

Author

Omar E. Pol, Dec 10 2008

Status

approved