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A167434 Diagonal sums of the Riordan array (1-4*x+4*x^2, x*(1-2*x)) (A167431). 2
1, -4, 5, -6, 13, -16, 25, -42, 57, -92, 141, -206, 325, -488, 737, -1138, 1713, -2612, 3989, -6038, 9213, -14016, 21289, -32442, 49321, -75020, 114205, -173662, 264245, -402072, 611569, -930562, 1415713, -2153700, 3276837, -4985126, 7584237 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (0,1,-2)

FORMULA

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

MATHEMATICA

LinearRecurrence[{0, 1, -2}, {1, -4, 5}, 100] (* G. C. Greubel, Jun 13 2016 *)

PROG

(PARI) x='x+O('x^40); Vec((1-4*x+4*x^2)/(1-x^2+2*x^3)) \\ G. C. Greubel, Jun 27 2018

(MAGMA) I:=[1, -4, 5]; [n le 3 select I[n] else Self(n-2) - 2*Self(n-3): n in [1..40]]; // G. C. Greubel, Jun 27 2018

CROSSREFS

Cf. A052947, A159287.

Sequence in context: A089119 A063833 A260107 * A139061 A029645 A191208

Adjacent sequences:  A167431 A167432 A167433 * A167435 A167436 A167437

KEYWORD

easy,sign

AUTHOR

Paul Barry, Nov 03 2009

STATUS

approved

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Last modified February 22 09:22 EST 2020. Contains 332133 sequences. (Running on oeis4.)