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

Author

Jonathan Vos Post, Apr 17 2008

Keywords

• easy
• nonn

Comments

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

Examples

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

Crossrefs

Cf. A007913, A069891.

Programs

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

Formula

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

Extensions

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