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A119330 Expansion of (1-x)^2/((1-x)^4-2x^4). 2
1, 2, 3, 4, 7, 18, 49, 120, 265, 554, 1155, 2476, 5455, 12138, 26881, 58992, 128689, 280466, 612579, 1341268, 2940151, 6443778, 14111857, 30886632, 67590649, 147934010, 323850531, 709047292, 1552412671, 3398703066, 7440375937 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Row sums of A119329. Binomial transform of A119332, or (1,1,0,0,2,2,0,0,4,4,...).

LINKS

Table of n, a(n) for n=0..30.

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

FORMULA

a(n)=4a(n-1)-6a(n-2)+4a(n-3)+a(n-4); a(n)=sum{k=0..n, sum{j=0..n-k, C(k,2j)C(n-k,2j)*2^j}}.

CROSSREFS

Sequence in context: A179985 A110705 A139439 * A084644 A208729 A270777

Adjacent sequences:  A119327 A119328 A119329 * A119331 A119332 A119333

KEYWORD

easy,nonn

AUTHOR

Paul Barry, May 14 2006

STATUS

approved

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Last modified February 16 15:17 EST 2020. Contains 331961 sequences. (Running on oeis4.)