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

1,4

Comments

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

Links

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

Formula

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

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

Mathematica

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

Prog

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

Crossrefs

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

Sequence in context: A343647 A218602 A114537 * A266413 A245614 A246165

Adjacent sequences: A243346 A243347 A243348 * A243350 A243351 A243352

Keyword

nonn

Author

Antti Karttunen, Jun 04 2014

Status

approved