A115046 G.f.: (1+x^2)^2*(x^4-6*x^3+1)/(x^2-1)^4.

1, 0, 6, -6, 20, -36, 50, -114, 104, -264, 190, -510, 316, -876, 490, -1386, 720, -2064, 1014, -2934, 1380, -4020, 1826, -5346, 2360, -6936, 2990, -8814, 3724, -11004, 4570, -13530, 5536, -16416, 6630, -19686, 7860, -23364, 9234, -27474, 10760, -32040, 12446, -37086, 14300, -42636, 16330

Offset: 0

Author

Roger L. Bagula, Feb 28 2006

Keywords

• sign
• easy

Comments

This sequence arose from an arithmetic error when computing A136264.

Links

• Index entries for linear recurrences with constant coefficients, signature (0,4,0,-6,0,4,0,-1).

Formula

a(n)= -n/12+3/4-n^3/6+3n^2/4+(-1)^n*(-3n^2/4+29n/12-3/4+n^3/3), n>0. [From R. J. Mathar, Mar 15 2009]

Extensions

Edited by N. J. A. Sloane, Dec 21 2006 and Apr 19 2008