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A118926 Invariant column vector V under matrix product A104546*V = V: a(n) = Sum_{k=0,[n/2]} A104546(n,k)*a(k). 1
1, 2, 7, 28, 125, 598, 3007, 15708, 84585, 466954, 2632167, 15103676, 88012801, 519848442, 3107443803, 18774545752, 114527169657, 704731976138, 4370943547471, 27306560735812, 171728169545661, 1086605771091766 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Triangle A104546(n,k) = the number of Schroeder paths of length 2n and having k platforms.

LINKS

Table of n, a(n) for n=0..21.

FORMULA

Self-convolution of A118927.

PROG

(PARI) {a(n)=local(G=1+x+x*O(x^n)); if(n==0, 1, for(i=0, n, G=1+x*G+x*G*(G+(y-1)*x/(1-x))); sum(k=0, n\2, a(k)*polcoeff(polcoeff(G+y*O(y^k), n, x), k, y)))}

CROSSREFS

Cf. A104546, A118927 (self-convolution square-root).

Sequence in context: A088702 A112565 A227845 * A127084 A252737 A217203

Adjacent sequences:  A118923 A118924 A118925 * A118927 A118928 A118929

KEYWORD

nonn

AUTHOR

Paul D. Hanna, May 06 2006

STATUS

approved

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Last modified August 10 14:50 EDT 2020. Contains 336381 sequences. (Running on oeis4.)