A081063 Number of numbers <= n that are 3-smooth or prime powers.

1, 2, 3, 4, 5, 6, 7, 8, 9, 9, 10, 11, 12, 12, 12, 13, 14, 15, 16, 16, 16, 16, 17, 18, 19, 19, 20, 20, 21, 21, 22, 23, 23, 23, 23, 24, 25, 25, 25, 25, 26, 26, 27, 27, 27, 27, 28, 29, 30, 30, 30, 30, 31, 32, 32, 32, 32, 32, 33, 33, 34, 34, 34, 35, 35, 35, 36, 36, 36, 36, 37, 38, 39

Offset

1,2

Comments

a(n) = #{A081061(k): 1<=k<=n}.

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Formula

a(n)=A071521(n)+A065515(n)-A000523(n)-A062153(n)+1.

Mathematica

Accumulate[Table[If[PrimePowerQ[n]||Max[FactorInteger[n][[All, 1]]]<5, 1, 0], {n, 80}]] (* Harvey P. Dale, Nov 29 2020 *)

Crossrefs

Cf. A003586, A000961.

Sequence in context: A128635 A353024 A100637 * A081304 A137721 A245339

Adjacent sequences: A081060 A081061 A081062 * A081064 A081065 A081066

Keyword

nonn

Author

Reinhard Zumkeller, Mar 04 2003

Status

approved