A072586 Number of numbers <= n having prime factors with odd exponents only.

0, 1, 2, 2, 3, 4, 5, 6, 6, 7, 8, 8, 9, 10, 11, 11, 12, 12, 13, 13, 14, 15, 16, 17, 17, 18, 19, 19, 20, 21, 22, 23, 24, 25, 26, 26, 27, 28, 29, 30, 31, 32, 33, 33, 33, 34, 35, 35, 35, 35, 36, 36, 37, 38, 39, 40, 41, 42, 43, 43, 44, 45, 45, 45, 46, 47, 48, 48, 49, 50, 51, 51, 52

Offset: 1

Author

Reinhard Zumkeller, Jun 23 2002

Keywords

• nonn

Links

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

Crossrefs

Cf. A000196, A002035, A065463, A295316.

Programs

Mathematica

Accumulate @ Table[If[n > 1 && AllTrue[FactorInteger[n][[;; , 2]], OddQ], 1, 0], {n, 1, 100}] (* Amiram Eldar, Sep 18 2022 *)

Formula

a(n) ~ c * n , where c = A065463. - Amiram Eldar, Sep 18 2022