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A217783 Expansion of (1-x)*(1-2x)/((1-5x+5*x^2)*(1-3x+x^2)). 1
1, 5, 21, 83, 318, 1196, 4445, 16389, 60097, 219527, 799734, 2907800, 10558041, 38297573, 138819053, 502925211, 1821362830, 6594366404, 23870720757, 86396702117, 312668994969, 1131463798415, 4094241931526, 14814592074288, 53603587025713, 193949782284101 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

A diagonal of the square array A217770.

LINKS

Table of n, a(n) for n=0..25.

FORMULA

a(n) = A217770(n,n+3).

a(n) = 8*a(n-1) -21*a(n-2) + 20*a(n-3) -5*a(n-4) for n>=4, a(0) = 1, a(1) = 5, a(2) = 21, a(3) = 83.

CROSSREFS

Cf. A217770, A217777, A217778, A217779, A217782.

Sequence in context: A094834 A303647 A147504 * A221862 A216271 A026017

Adjacent sequences:  A217780 A217781 A217782 * A217784 A217785 A217786

KEYWORD

nonn,easy

AUTHOR

Philippe Deléham, Mar 24 2013

STATUS

approved

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Last modified August 19 20:38 EDT 2022. Contains 356231 sequences. (Running on oeis4.)