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A188444 Expansion of (1+x)*(1+x+x^2)*(1-x+x^2-4*x+x^4-x^5+x^6)/(1+x^4)^3. 1
1, 1, 1, -3, -9, -9, -6, 10, 25, 25, 15, -21, -49, -49, -28, 36, 81, 81, 45, -55, -121, -121, -66, 78, 169, 169, 91, -105, -225, -225, -120, 136, 289, 289, 153, -171, -361, -361, -190, 210, 441, 441, 231, -253, -529, -529, -276, 300, 625, 625, 325 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

a(n+1) is the Hankel transform of A166300(n+3) (diagonal sums of the triangle A100754).

LINKS

Table of n, a(n) for n=0..50.

Index entries for linear recurrences with constant coefficients, signature (0,0,0,-3,0,0,0,-3,0,0,0,-1).

FORMULA

G.f.: (1+x+x^2-3*x^3-6*x^4-6*x^5-3*x^6+x^7+x^8+x^9)/(1+x^4)^3.

CROSSREFS

Sequence in context: A268107 A306963 A084762 * A201409 A111120 A100401

Adjacent sequences:  A188441 A188442 A188443 * A188445 A188446 A188447

KEYWORD

sign,easy

AUTHOR

Paul Barry, Mar 31 2011

STATUS

approved

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Last modified June 2 09:31 EDT 2020. Contains 334769 sequences. (Running on oeis4.)