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1, 3, 16, 114, 1013, 10973, 142980, 2208958, 39796747, 822252765, 19192927840, 499725372072, 14361189358332, 451551559895244, 15419952421504604, 568327808746891014, 22486286328779957223, 950624702855155671101, 42765431507866487733504, 2039838152324158031743570
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,2
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LINKS
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Table of n, a(n) for n=0..19.
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FORMULA
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a(n) = (binomial(1 + 3*n, n)*2F1([1, -n], [-1 - 3*n], 1 + n)/(1 + n), where 2F1 is the hypergeometric function.
a(n) ~ exp(3) * n^(n-1). - Vaclav Kotesovec, Nov 06 2019
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MATHEMATICA
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Table[(Binomial[1+3n, n]Hypergeometric2F1[1, -n, -1-3n, 1+n])/(1+n), {n, 0, 19}]
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CROSSREFS
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Cf. A007318, A329058.
Sequence in context: A124537 A305133 A074523 * A042437 A324514 A334786
Adjacent sequences: A329110 A329111 A329112 * A329114 A329115 A329116
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KEYWORD
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nonn
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AUTHOR
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Stefano Spezia, Nov 05 2019
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STATUS
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approved
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