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A184554 Self-convolution equals A184553. 1
1, 3, 35, 474, 6891, 104360, 1623050, 25718472, 413215707, 6710439939, 109904635992, 1812533851286, 30064278051066, 501094410251724, 8386624585529736, 140867399832201392, 2373517896651329211 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..16.

FORMULA

Sum_{k=0..n} a(n-k)*a(k) = Sum_{k=0..n} C(3n+k,n-k)*C(4n-k,k).

EXAMPLE

G.f.: A(x) = 1 + 3*x + 35*x^2 + 474*x^3 + 6891*x^4 + 104360*x^5 +...

A(x)^2 = 1 + 6*x + 79*x^2 + 1158*x^3 + 17851*x^4 + 283246*x^5 + 4579306*x^6 +...+ A184553(n)*x^n +...

PROG

(PARI) {a(n)=local(A2=sum(m=0, n, sum(k=0, m, binomial(3*m+k, m-k)*binomial(4*m-k, k))*x^m+x*O(x^n))); polcoeff(A2^(1/2), n)}

CROSSREFS

Cf. A184553, A183161.

Sequence in context: A179135 A100033 A259557 * A046032 A304191 A009071

Adjacent sequences:  A184551 A184552 A184553 * A184555 A184556 A184557

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Jan 16 2011

STATUS

approved

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Last modified September 15 04:09 EDT 2019. Contains 327062 sequences. (Running on oeis4.)