A331002 a(n) is the real part of f(n) (as defined in A330779).

0, 0, -2, -2, 1, 1, -2, -2, 2, 2, -3, -3, 3, 3, -2, -2, 3, 3, -4, -4, 2, 2, -4, -4, 4, 4, -3, -3, 5, 5, -2, -2, 6, 6, -4, -4, 4, 4, -5, -5, 5, 5, -4, -4, 5, 5, -6, -6, 3, 3, -6, -6, 6, 6, -5, -5, 6, 6, -4, -4, 6, 6, -7, -7, 3, 3, -8, -8, 4, 4, -7, -7, 7, 7, -6

Offset: 0

Author

Rémy Sigrist, Jan 05 2020

Keywords

• sign

Links

• Rémy Sigrist, Table of n, a(n) for n = 0..10000
• Rémy Sigrist, PARI program for A331002

Crossrefs

Cf. A330779.

Programs

PARI

See Links section.

Formula

a(2*k+1) = a(2*k) for any k >= 0.

a(2*k) = a(2*k-1) + A330779(2*k) * (-1)^k for any k > 0.