id:A102214 - OEIS Search Results

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G.f. (4*x^2+4*x+1)/((x+1)(x-1)^3).

+0
2

1, 6, 16, 30, 49, 72, 100, 132, 169, 210, 256, 306, 361, 420, 484, 552, 625, 702, 784, 870, 961, 1056, 1156, 1260, 1369, 1482, 1600, 1722, 1849, 1980, 2116, 2256, 2401, 2550, 2704, 2862, 3025, 3192, 3364, 3540, 3721, 3906, 4096, 4290, 4489, 4692, 4900 (list; graph; listen)

	OFFSET	`0,2`
	COMMENT	`A floretion-generated sequence.` `a(n) gives the number of triples (x,y,x+y) with positive integers holding x < y and x + y <= 3*n. - Marcus Schmidt (marcus-schmidt(AT)gmx.net), Jan 13 2006`
	LINKS	`Index entries for sequences related to linear recurrences with constant coefficients`
	FORMULA	`a(2n) = A016778(n) = (3n+1)^2; a(n) + a(n+1) = A038764(n) (conjecture)` `a(n) = FLOOR( (3n - 1)/2 ) CEIL( (3n - 1)/2 ). If n is even then a(n) = ((3n - 1)/2)^2 - (1/2)^2. If n is odd then a(n) = ((3*n - 1)/2)^2. - Marcus Schmidt (marcus-schmidt(AT)gmx.net), Jan 13 2006`
	CROSSREFS	`Cf. A016778, A038764.` `Sequence in context: A032422 A054000 A113742 this_sequence A115007 A005891 A092286` `Adjacent sequences: A102211 A102212 A102213 this_sequence A102215 A102216 A102217`
	KEYWORD	`easy,nonn`
	AUTHOR	`Creighton Dement (creighton.k.dement(AT)uni-oldenburg.de), Feb 17 2005`

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Last modified November 27 22:38 EST 2009. Contains 167602 sequences.

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