A243349 Difference between the n-th squarefree number and the index of its largest prime factor.

1, 1, 1, 2, 4, 3, 7, 6, 7, 10, 12, 10, 11, 17, 17, 14, 20, 19, 27, 20, 28, 27, 31, 25, 30, 33, 28, 38, 29, 37, 32, 44, 37, 50, 49, 48, 42, 43, 51, 59, 61, 48, 60, 66, 51, 52, 62, 72, 72, 57, 69, 60, 78, 72, 77, 65, 85, 82, 79, 87, 72, 75, 95, 76, 101, 90, 79, 80, 105

Offset: 1

Author

Antti Karttunen, Jun 04 2014

Keywords

• nonn

Comments

Different from A243289. A243348 gives the difference a(n) - A243289(n).

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10001

Crossrefs

Cf. A005117, A243289, A243290, A243291, A243348.

Programs

Mathematica

With[{s = Select[Range[120], SquareFreeQ]}, s - Table[PrimePi[FactorInteger[k][[-1, 1]]], {k, s}]] (* Amiram Eldar, Mar 04 2024 *)

Scheme

(define (A243349 n) (A243291 (A005117 n)))

Formula

a(n) = A243291(A005117(n)).

a(n) = A005117(n) - A061395(A005117(n)).