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A187117
A diagonal of triangle A187115.
4
1, 6, 39, 318, 3242, 40348, 598083, 10337402, 204706486, 4577520108, 114208773268, 3147671423964, 95023271024164, 3119560618275648, 110684959354534001, 4221624141483353436, 172274971776090819870
OFFSET
2,2
COMMENTS
Definition of triangle: A187115(n,k) = [y^k] R_{n-1}(y+y^2) for k=2..n, n>2, where R_n(y) is the n-th row polynomial with R_2(y)=y^2.
FORMULA
Equals column 1 in the matrix cube of triangle A135080.
PROG
(PARI) {a(n)=local(Rn=y^2); for(m=2, n+2, Rn=subst(truncate(Rn), y, y+y^2+O(y^m))); polcoeff(Rn, n, y)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Mar 08 2011
STATUS
approved