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A097095
Main diagonal of triangle A097094; g.f. A(x) satisfies A(x)/(1-x-x^2) = A(x^2)^2/(1-x-x^3)^2.
3
1, 1, 2, 3, 7, 8, 15, 19, 37, 42, 66, 76, 122, 114, 148, 90, 77, -213, -574, -1511, -2860, -5773, -10209, -18310, -30884, -52778, -87051, -143621, -232157, -375464, -599112, -953504, -1504430, -2368510, -3706276, -5782850, -8984526, -13924596, -21511458, -33151454, -50964864, -78187890
OFFSET
0,3
FORMULA
G.f.: A(x)/(1-x-x^2) = g.f. of A097096 (row sums of A097094); G.f.: A(x^2)/(1-x-x^3) = g.f. of A097097 (antidiagonal sums of A097094).
PROG
(PARI) {a(n)=local(A=1+x+x*O(x^n)); for(i=0, n+2, B=subst(A^2, x, x^2); A=(A+B*(1-x-x^2)/(1-x-x^3+x*O(x^n))^2)/2); round(polcoeff(A+x*O(x^n), n))}
CROSSREFS
KEYWORD
sign
AUTHOR
Paul D. Hanna, Jul 26 2004
STATUS
approved