A076480 a(n) = n + mu(rad(n)), where mu is the Moebius function (A008683) and rad is the squarefree kernel (A007947).

2, 1, 2, 3, 4, 7, 6, 7, 8, 11, 10, 13, 12, 15, 16, 15, 16, 19, 18, 21, 22, 23, 22, 25, 24, 27, 26, 29, 28, 29, 30, 31, 34, 35, 36, 37, 36, 39, 40, 41, 40, 41, 42, 45, 46, 47, 46, 49, 48, 51, 52, 53, 52, 55, 56, 57, 58, 59, 58, 59, 60, 63, 64, 63, 66, 65, 66, 69, 70, 69, 70, 73

Offset

1,1

Links

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

Formula

a(n) = n + A076479(n) = n + A008683(A007947(n)).

Mathematica

a[n_] := n + (-1)^PrimeNu[n]; Array[a, 100] (* Amiram Eldar, Apr 10 2025 *)

Prog

(PARI) a(n)=n+(-1)^omega(n) \\ Charles R Greathouse IV, Aug 08 2013

Crossrefs

Cf. A007947, A008683, A076479.

Sequence in context: A396883 A350404 A325841 * A002730 A081664 A224926

Adjacent sequences: A076477 A076478 A076479 * A076481 A076482 A076483

Keyword

nonn,easy

Author

Reinhard Zumkeller, Oct 14 2002

Status

approved