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%I #5 Nov 06 2019 17:50:48
%S 1,1,2,4,11,30,103,354,1440,5911,27651,131062,690543,3693765,21585068,
%T 128165652,820859645,5343318222,37155889171,262577578134,
%U 1967281479508,14975397597557,120122032987319,978625889818014,8359402026954939,72495015037575673,656446920912518700
%N a(-1) = 1, a(n) = Sum_{k=0..n} A034851(n,k)*a(k-1) where A034851(n,k) are entries in Losanitsch's triangle.
%H Andrew Howroyd, <a href="/A102814/b102814.txt">Table of n, a(n) for n = -1..200</a>
%o (PARI) \\ here T(n,k) is A034851(n,k).
%o T(n, k) = {(1/2)*(binomial(n, k) + binomial(n%2, k%2) * binomial(n\2, k\2))}
%o seq(n)={my(a=vector(n+1)); a[1]=1; for(n=1, n, a[n+1]=sum(k=1, n, a[k]*T(n-1,k-1))); a} \\ _Andrew Howroyd_, Nov 06 2019
%Y Cf. A034851.
%K nonn
%O -1,3
%A _Gerald McGarvey_, Feb 26 2005
%E Terms a(12) and beyond from _Andrew Howroyd_, Nov 06 2019