id:A025240 - OEIS Search Results

Search: id:A025240

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

+0
3

3, 2, 6, 22, 90, 394, 1806, 8558, 41586, 206098, 1037718, 5293446, 27297738, 142078746, 745387038, 3937603038, 20927156706, 111818026018, 600318853926, 3236724317174, 17518619320890, 95149655201962, 518431875418926, 2832923350929742 (list; graph; listen)

	OFFSET	`1,1`
	FORMULA	`G.f.: (1+3x-sqrt(1-6x+x^2))/2 - Michael Somos, Jun 08, 2000.`
	PROGRAM	`(PARI) a(n)=polcoeff((1+3x-sqrt(1-6x+x^2+x*O(x^n)))/2, n)`
	CROSSREFS	`Essentially same as A006318.` `Adjacent sequences: A025237 A025238 A025239 this_sequence A025241 A025242 A025243` `Sequence in context: A082561 A110768 A140230 this_sequence A137602 A018864 A019951`
	KEYWORD	`nonn`
	AUTHOR	`Clark Kimberling (ck6(AT)evansville.edu)`

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Last modified November 9 12:23 EST 2009. Contains 166233 sequences.

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