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A025182 a(n) = number of (s(0), s(1), ..., s(n)) such that s(i) is an integer, s(0) = 0, |s(1)| = 1, |s(i) - s(i-1)| <= 1 for i >= 2, s(n) = 4. Also a(n) = T(n,n-4), where T is the array defined in A025177. 3
1, 4, 16, 56, 189, 616, 1968, 6192, 19272, 59488, 182468, 556920, 1693146, 5131296, 15511344, 46791072, 140905197, 423709956, 1272596136, 3818355464, 11447074309, 34292702840, 102670377120, 307230479920, 918951019155, 2747624937876 (list; graph; refs; listen; history; text; internal format)
OFFSET

4,2

COMMENTS

Apparently first differences of A014533.

LINKS

Table of n, a(n) for n=4..29.

FORMULA

Conjecture: -(n-4)*(n+4)*a(n) +(4*n^2-7*n-29)*a(n-1) +(-2*n^2+17*n-2)*a(n-2) -(4*n+1)*(n-3)*a(n-3) +3*(n-3)*(n-4)*a(n-4)=0. - R. J. Mathar, Feb 25 2015

Conjecture: -(n-4)*(n+4)*(n^2-3*n+6)*a(n) +(n-1)*(2*n^3-5*n^2+11*n-36)*a(n-1) +3*(n-1)*(n-2)*(n^2-n+4)*a(n-2)=0. - R. J. Mathar, Feb 25 2015

CROSSREFS

Sequence in context: A109634 A026126 A026155 * A057585 A255301 A097128

Adjacent sequences:  A025179 A025180 A025181 * A025183 A025184 A025185

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified December 15 17:03 EST 2019. Contains 330000 sequences. (Running on oeis4.)