A185964 Diagonal sums of number triangle A185962.

1, -1, 0, -2, 1, 0, 4, 0, 1, -7, -3, -5, 10, 9, 16, -9, -17, -40, -6, 19, 82, 54, 10, -135, -161, -127, 153, 340, 433, 0, -527, -1053, -620, 434, 2013, 2200, 712, -2880, -5267, -4491, 1981, 9635, 13350, 4897, -12392

Offset: 0

Author

Paul Barry, Feb 07 2011

Keywords

• sign
• easy

Links

• G. C. Greubel, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (1,0,-2,1).

Crossrefs

Cf. A185962.

Programs

Mathematica

CoefficientList[Series[(1 - x)^2/(1 - x + 2*x^3 - x^4), {x, 0, 50}], x] (* G. C. Greubel, Jul 23 2017 *)

PARI

x='x+O('x^50); Vec((1 - x)^2/(1 - x + 2*x^3 - x^4)) \\ G. C. Greubel, Jul 23 2017

Formula

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

a(n) = Sum_{k=0..floor(n/2)} A185962(n-k,k).

Extensions

More terms from Philippe Deléham, Feb 07 2012