id:A116090 - OEIS Search Results

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Expansion of 1/(1-x^2*(1+x)^3).

+0
2

1, 0, 1, 3, 4, 7, 16, 29, 52, 102, 194, 361, 685, 1301, 2452, 4633, 8771, 16577, 31327, 59241, 112004, 211724, 400285, 756786, 1430710, 2704817, 5113647, 9667590, 18277014, 34553692, 65325542, 123501151, 233485250, 441415867, 834519021 (list; graph; listen)

	OFFSET	`0,4`
	COMMENT	`Diagonal sums of number triangle A116090.`
	FORMULA	`a(n)=a(n-2)+3a(n-3)+3a(n-4)+a(n-5); a(n)=sum{k=0..floor(n/2), C(3k,n-2k)}=sum{k=0..floor(n/2), C(n-k,k)C(4k,n-k)/C(4k,k)}.`
	CROSSREFS	`Adjacent sequences: A116087 A116088 A116089 this_sequence A116091 A116092 A116093` `Sequence in context: A024368 A027020 A130755 this_sequence A100455 A078825 A093611`
	KEYWORD	`easy,nonn`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), Feb 04 2006`

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Last modified October 6 16:13 EDT 2008. Contains 144667 sequences.

AT&T Labs Research