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A026014 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) = 2, s(2n) = 6. Also a(n) = T(2n,n-2), where T is the array defined in A026009. 1
1, 6, 28, 119, 483, 1911, 7448, 28764, 110466, 422807, 1615152, 6163885, 23514855, 89714835, 342411120, 1307613480, 4997082510, 19111589280, 73154916744, 280265589198, 1074685552094, 4124573481446, 15843809385168, 60914041121640 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

LINKS

Table of n, a(n) for n=2..25.

FORMULA

Conjecture: -(n-2)*(n+5)*(n+23)*a(n) +(-n^3+127*n^2+188*n-432)*a(n-1) +2*(n-1)*(2*n-3)*(5*n-24)*a(n-2)=0. - R. J. Mathar, Jun 20 2013

CROSSREFS

First differences of A000588.

Sequence in context: A089096 A229587 A230492 * A226853 A259307 A183019

Adjacent sequences:  A026011 A026012 A026013 * A026015 A026016 A026017

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified October 21 02:22 EDT 2018. Contains 316405 sequences. (Running on oeis4.)