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A187006
A diagonal of triangle A187005.
5
1, 2, 6, 29, 202, 1880, 22108, 315784, 5322126, 103541022, 2285965792, 56501970700, 1546339364952, 46433615292128, 1518172222889000, 53695946069029290, 2042960241832903824, 83207255745283689726
OFFSET
1,2
COMMENTS
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.
PROG
(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)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Mar 02 2011
STATUS
approved