id:A025251 - OEIS Search Results

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a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-3)*a(3) for n >= 4.

+0
2

0, 1, 2, 0, 2, 4, 2, 12, 18, 24, 82, 120, 242, 620, 1010, 2324, 5154, 9520, 22178, 46512, 94178, 214548, 446690, 952732, 2122034, 4475592, 9776626, 21491496, 46096338, 101585276, 222360530, 483573796, 1068438594, 2341596256, 5140674882, 11369018464 (list; graph; listen)

	OFFSET	`1,3`
	FORMULA	`G.f.: (1+x^2-sqrt(1-2x^2-8x^3+x^4))/2 - Michael Somos, Jun 08, 2000.`
	PROGRAM	`(PARI) a(n)=polcoeff((x^2-sqrt(1-2x^2-8x^3+x^4+x*O(x^n)))/2, n)`
	CROSSREFS	`Sequence in context: A015910 A023987 A021498 this_sequence A011119 A120553 A078023` `Adjacent sequences: A025248 A025249 A025250 this_sequence A025252 A025253 A025254`
	KEYWORD	`nonn`
	AUTHOR	`Clark Kimberling (ck6(AT)evansville.edu)`

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Last modified July 19 08:04 EDT 2008. Contains 142098 sequences.

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