id:A121689 - OEIS Search Results

Search: id:A121689

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G.f.: A(x) = Sum_{k>=0} x^k * (1+x)^(k^2).

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1, 1, 2, 5, 16, 57, 231, 1023, 4926, 25483, 140601, 822422, 5074015, 32881868, 223027542, 1578435549, 11625317128, 88894615929, 704269188135, 5770209550496, 48810504348082, 425650324975153, 3821377057170313 (list; graph; listen)

	OFFSET	`0,3`
	FORMULA	`a(n) = Sum_{k=0..n} C(k^2,n-k).`
	PROGRAM	`(PARI) a(n)=sum(k=0, n, binomial(k^2, n-k))`
	CROSSREFS	`Sequence in context: A082789 A072110 A114296 this_sequence A009225 A157612 A149978` `Adjacent sequences: A121686 A121687 A121688 this_sequence A121690 A121691 A121692`
	KEYWORD	`nonn`
	AUTHOR	`Paul D. Hanna (pauldhanna(AT)juno.com), Aug 15 2006`

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Last modified December 15 00:47 EST 2009. Contains 170825 sequences.

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