id:A025228 - OEIS Search Results

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a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-1)*a(1) for n >= 3.

+0
3

2, 1, 4, 17, 76, 354, 1704, 8421, 42508, 218318, 1137400, 5996938, 31940792, 171605956, 928931280, 5061593709, 27739833228, 152809506582, 845646470616, 4699126915422, 26209721959656, 146681521121244, 823429928805936, 4635568494271458 (list; graph; listen)

	OFFSET	`1,1`
	FORMULA	`G.f.: (1-sqrt(1-8x+12x^2))/2 - Michael Somos, Jun 08, 2000.`
	PROGRAM	`(PARI) a(n)=polcoeff((1-sqrt(1-8x+12x^2+x*O(x^n)))/2, n)`
	CROSSREFS	`Essentially A005572 shifted right twice.` `Sequence in context: A162977 A032174 A087801 this_sequence A132945 A013156 A012925` `Adjacent sequences: A025225 A025226 A025227 this_sequence A025229 A025230 A025231`
	KEYWORD	`nonn`
	AUTHOR	`Clark Kimberling (ck6(AT)evansville.edu)`

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Last modified December 7 08:40 EST 2009. Contains 170430 sequences.

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