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 square of triangle A135080.
PROG
(PARI) {a(n)=local(Rn=y^2); for(m=2, n+1, 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