A293665 a(0) = 1; a(n) = -Sum_{d|n} a(n-d).

1, -1, 0, -1, 0, -1, 1, -2, 0, -2, 2, -3, 1, -2, 2, -6, 2, -3, 7, -8, 2, -12, 12, -13, 0, -3, 4, -12, 17, -18, 19, -20, -19, -13, 34, -71, 54, -55, 8, -67, 73, -74, 79, -80, -72, -154, 238, -239, 39, -119, 163, -237, 97, -98, 310, -402, -22, -297, 336, -337, 271, -272, 20, -659, 369, -738

Offset: 0

Author

Ilya Gutkovskiy, Oct 14 2017

Keywords

• sign

Links

• Ilya Gutkovskiy, Extended graphical example

Crossrefs

Cf. A067951, A281487, A281488.

Programs

Mathematica

a[n_] := a[n] = -Sum[a[n - d], {d, Divisors[n]}]; a[0] = 1; Table[a[n], {n, 0, 65}]

Formula

a(p) = -a(p-1) - 1, for p is a prime.