A127513 Partial sums of A127511.

1, -1, -5, -5, -21, 11, -53, -53, -53, 459, -565, -565, -4661, 3531, 19915, 19915, -45621, -45621, -307765, -307765, 740811, 2837963, -1356341, -1356341, -1356341, 32198091, 32198091, 32198091, -236237365, -773108277

Offset: 1

Author

Gary W. Adamson, Jan 17 2007

Keywords

• sign

Examples

			a(3) = -5 = (1 - 2 - 4).
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A127511, A127512.

Programs

Maple

a:= proc(n) option remember;
      numtheory[mobius](n)*2^(n-1) +`if`(n=1, 0, a(n-1))
    end:
seq(a(n), n=1..30);  # Alois P. Heinz, Apr 04 2012

Mathematica

Table[2^(n-1) MoebiusMu[n], {n, 1, 30}] // Accumulate (* Jean-François Alcover, May 21 2020 *)

Extensions

More terms from R. J. Mathar, Apr 04 2012