id:A025178 - OEIS Search Results

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a(n) = number of (s(0), s(1), ..., s(n)) such that s(i) is an integer, s(0) = 0 = s(n), |s(1)| = 1, |s(i) - s(i-1)| <= 1 for i >= 2. Also a(n) = T(n,n), where T is the array defined in A025177.

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2

2, 4, 12, 32, 90, 252, 714, 2032, 5814, 16700, 48136, 139152, 403286, 1171380, 3409020, 9938304, 29017878, 84844044, 248382516, 727971360, 2135784798, 6272092596, 18435108258, 54228499920, 159636389850, 470256930052, 1386170197704 (list; graph; listen)

	OFFSET	`2,1`
	COMMENT	`First differences of the central trinomial coefficients A002426. Note that n-1 divides a(n). - T. D. Noe (noe(AT)sspectra.com), Mar 16 2005`
	FORMULA	`a(n)=A002426(n+1)-A002426(n); a(n) is asymptotic to c*3^n/sqrt(n) with c around 1.02... - Benoit Cloitre, Nov 02, 2002`
	CROSSREFS	`Sequence in context: A028860 A106433 A026151 this_sequence A087211 A039721 A002528` `Adjacent sequences: A025175 A025176 A025177 this_sequence A025179 A025180 A025181`
	KEYWORD	`nonn`
	AUTHOR	`Clark Kimberling (ck6(AT)evansville.edu)`

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Last modified July 4 18:25 EDT 2008. Contains 140886 sequences.

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