id:A026031 - OEIS Search Results

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a(n) = number of (s(0), s(1), ..., s(2n)) such that s(i) is a nonnegative integer and |s(i) - s(i-1)| = 1 for i = 1,2,...,n, s(0) = 3, s(2n) = 7. Also a(n) = T(2n,n-2), where T is defined in A026022.

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1, 6, 28, 120, 494, 1988, 7888, 31008, 121125, 471086, 1826660, 7068360, 27313650, 105452700, 406923360, 1569869760, 6056194410, 23366193084, 90173331960, 348102883184, 1344324544156, 5193831553416, 20075820280544, 77637309982400 (list; graph; listen)

	OFFSET	`2,2`
	FORMULA	`C(2n, n-2) - C(2n, n-6). G.f.: (1+x^2C^4)*C^6, where C=(1-sqrt(1-4x))/(2x). - Ralf Stephan, Jan 09 2005`
	CROSSREFS	`Sequence in context: A055717 A090777 A055715 this_sequence A002694 A007691 A065997` `Adjacent sequences: A026028 A026029 A026030 this_sequence A026032 A026033 A026034`
	KEYWORD	`nonn`
	AUTHOR	`Clark Kimberling (ck6(AT)evansville.edu)`

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.

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