

A229452


G.f.: exp( Sum_{n>=1} (3*n)!/(3!*n!^3) * x^n/n ).


2



1, 1, 8, 101, 1569, 27445, 518407, 10333243, 214320244, 4583132411, 100411556533, 2243625355010, 50955869372055, 1173262656151429, 27332509319090516, 643208905017756216, 15270427859720369204, 365356267775348553277, 8801688936499808334602
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OFFSET

0,3


COMMENTS

Selfconvolution 6th power yields A229451.


LINKS

Table of n, a(n) for n=0..18.


EXAMPLE

G.f.: A(x) = 1 + 6*x + 63*x^2 + 866*x^3 + 13899*x^4 + 246366*x^5 +...
where
log(A(x)) = x + 15*x^2/2 + 280*x^3/3 + 5775*x^4/4 + 126126*x^5/5 + 2858856*x^6/6 +...+ A060542(n)*x^n/n +...


PROG

(PARI) {a(n)=polcoeff(exp(sum(k=1, n, (3*k)!/(3!*k!^3)*x^k/k) +x*O(x^n)), n)}
for(n=0, 25, print1(a(n), ", "))


CROSSREFS

Cf. A229451, A060542, A006480 (De Bruijn's S(3,n)).
Sequence in context: A317598 A238947 A291536 * A199816 A302870 A317862
Adjacent sequences: A229449 A229450 A229451 * A229453 A229454 A229455


KEYWORD

nonn


AUTHOR

Paul D. Hanna, Sep 23 2013


STATUS

approved



