id:A026289 - OEIS Search Results

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a(n) = number of (s(0), s(1), ..., s(n)) such that every s(i) is an integer, s(0) = 0, s(1) = 1, s(n) = 3, |s(i) - s(i-1)| <= 1 for i >= 2, |s(2) - s(1)| = 1, |s(3) - s(2)| = 1 if s(2) = 1. Also a(n) = T(n,n-3), where T is the array in A026268.

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1, 3, 9, 27, 79, 229, 659, 1889, 5402, 15430, 44054, 125786, 359296, 1026936, 2937444, 8409540, 24097737, 69118635, 198442329, 570286939, 1640469427, 4723363073, 13612376671, 39265012213, 112248893147, 327545797361, 947203621523 (list; graph; listen)

	OFFSET	`3,2`
	FORMULA	`G.f.: 16z^3(1-z)(1-z^2)/[1-z+sqrt(1-2z-3z^2)]^4.`
	CROSSREFS	`Pairwise sums of A026124.` `Sequence in context: A006810 A090401 A113041 this_sequence A027129 A077844 A077827` `Adjacent sequences: A026286 A026287 A026288 this_sequence A026290 A026291 A026292`
	KEYWORD	`nonn`
	AUTHOR	`Clark Kimberling (ck6(AT)evansville.edu)`

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

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