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A098484 Expansion of 1/sqrt((1-x)^2-12x^4). 2
1, 1, 1, 1, 7, 19, 37, 61, 145, 397, 979, 2107, 4591, 10915, 26857, 63649, 146347, 339751, 808885, 1936717, 4588705, 10803133, 25559287, 60893551, 145231309, 345462145, 821110051, 1955736379, 4668132067, 11146642903, 26605635949 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

1/sqrt((1-x)^2-4rx^4) expands to sum{k=0..floor(n/2), binomial(n-2k,k)binomial(n-3k,k)r^k}

LINKS

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

FORMULA

a(n)=sum{k=0..floor(n/2), binomial(n-2k, k)binomial(n-3k, k)3^k}

CROSSREFS

Cf. A098481, A098482, A098483.

Sequence in context: A003215 A133323 A002407 * A155443 A155405 A155448

Adjacent sequences:  A098481 A098482 A098483 * A098485 A098486 A098487

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Sep 10 2004

STATUS

approved

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Last modified April 20 06:17 EDT 2014. Contains 240779 sequences.