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A143685 Pascal-(1,9,1) array. 0
1, 1, 1, 1, 11, 1, 1, 21, 21, 1, 1, 31, 141, 31, 1, 1, 41, 361, 361, 41, 1, 1, 51, 681, 1991, 681, 51, 1, 1, 61, 1101, 5921, 5921, 1101, 61, 1, 1, 71, 1621, 13151, 29761, 13151, 1621, 71, 1, 1, 81, 2241, 24681, 96201 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

Table of n, a(n) for n=0..49.

FORMULA

Number triangle T(n,k)=sum{j=0..n-k, binomial(n-k,j)binomial(k,j)10^j} Riordan array (1/(1-x),x(1+9x)/(1-x)). As a square array read by diagonals T(n, 0)=T(0, k)=1, T(n, k)=T(n, k-1)+9T(n-1, k-1)+T(n-1, k).

MATHEMATICA

Table[ Hypergeometric2F1[-k, k-n, 1, 10], {n, 0, 9}, {k, 0, n}] // Flatten (* Jean-Fran├žois Alcover, May 24 2013 *)

CROSSREFS

Cf. A143680, A143682.

Sequence in context: A214326 A105769 A157171 * A168647 A202767 A060270

Adjacent sequences:  A143682 A143683 A143684 * A143686 A143687 A143688

KEYWORD

easy,nonn,tabl

AUTHOR

Paul Barry, Aug 28 2008

STATUS

approved

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Last modified September 21 00:17 EDT 2019. Contains 327252 sequences. (Running on oeis4.)