A137427 Squarefree part of partial sum of squarefree part of n.

1, 3, 6, 7, 3, 2, 1, 3, 7, 38, 1, 13, 65, 79, 94, 95, 7, 114, 133, 138, 159, 181, 51, 210, 211, 237, 15, 247, 69, 34, 337, 339, 93, 406, 1, 442, 479, 517, 139, 566, 607, 649, 173, 703, 177, 754, 89, 201, 805, 807, 858, 871, 231, 930, 985, 111, 66, 1114, 1173, 33, 1249

Offset

1,2

Comments

Core(partial sum(core(n))) where "core" means "squarefree part."

Links

Table of n, a(n) for n=1..61.

Formula

a(n)=A007913(A069891(n)). - R. J. Mathar, Apr 23 2008

Example

a(35) = 1 because A007913( A069891(35) ) = A007913(441) = A007913(21^2) = 1.

Maple

A007913 := proc(n) local a, f ; a := 1 ; for f in ifactors(n)[2] do if op(2, f) mod 2 <> 0 then a := a*op(1, f) ; fi ; od: a ; end: A069891 := proc(n) add( A007913(k), k=1..n) ; end: A137427 := proc(n) A007913(A069891(n)) ; end: seq(A137427(n), n=1..100) ; # R. J. Mathar, Apr 23 2008

Crossrefs

Cf. A007913, A069891.

Sequence in context: A275696 A080260 A065269 * A177035 A055102 A243976

Adjacent sequences: A137424 A137425 A137426 * A137428 A137429 A137430

Keyword

easy,nonn

Author

Jonathan Vos Post, Apr 17 2008

Extensions

Edited and extended by R. J. Mathar, Apr 23 2008

Status

approved