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A187006 A diagonal of triangle A187005. 5


%S 1,2,6,29,202,1880,22108,315784,5322126,103541022,2285965792,

%T 56501970700,1546339364952,46433615292128,1518172222889000,

%U 53695946069029290,2042960241832903824,83207255745283689726

%N A diagonal of triangle A187005.

%C Definition of triangle: A187005(n,k) = [y^k] R_{n-1}(y+y^2) for k=1..n where R_n(y) is the n-th row polynomial for n>1 with R_1(y)=y.

%o (PARI) {a(n)=local(Rn=y);for(m=1,n+1,Rn=subst(truncate(Rn),y,y+y^2+y*O(y^m)));polcoeff(Rn,n,y)}

%Y Cf. A187005, A135081, A187007, A187008, A187009.

%K nonn

%O 1,2

%A _Paul D. Hanna_, Mar 02 2011

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Last modified September 26 20:34 EDT 2021. Contains 347672 sequences. (Running on oeis4.)