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A184358 a(n) = (n+1)!^2/2^n. 3
1, 2, 9, 72, 900, 16200, 396900, 12700800, 514382400, 25719120000, 1556006760000, 112032486720000, 9466745127840000, 927741022528320000, 104370865034436000000, 13359470724407808000000, 1930443519676928256000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

FORMULA

Self-convolution of A184359.

EXAMPLE

G.f.: A(x) = 1 + 2*x + 9*x^2 + 72*x^3 + 900*x^4 + 16200*x^5 +...

A(x)^(1/2) = 1 + x + 4*x^2 + 32*x^3 + 410*x^4 + 7562*x^5 + 188736*x^6 +...+ A184359(n)*x^n +...

PROG

(PARI) {a(n)=(n+1)!^2/2^n}

CROSSREFS

Cf. A184359, A184360, A184361, A006472.

Sequence in context: A133984 A208898 A108995 * A132843 A346648 A336955

Adjacent sequences:  A184355 A184356 A184357 * A184359 A184360 A184361

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Jan 16 2011

STATUS

approved

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Last modified September 18 19:30 EDT 2021. Contains 347534 sequences. (Running on oeis4.)