A277298 - OEIS

A277298

Central terms of triangle A277295 in odd-indexed rows; a(n) = A277295(2*n-1,n-1).

1, 2, 76, 5404, 535410, 66031704, 9583782716, 1584902128648, 292586323812088, 59462699504146980, 13171171610678351360, 3155802303880338506184, 813045290972961285049576, 224143228528852050484555760, 65850557807967931843625040120, 20543425063284611418233827507248, 6784261706348459523065200262509390

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OFFSET

1,2

COMMENTS

G.f. G(x,y) of triangle A277295 satisfies:

(1) G(x,y) = x + G( y*G(x,y) + (1-y)*x, y)^2.

(2) G( x - y*G(x,y)^2, y) = x + (1-y)*G(x,y)^2.

LINKS

Table of n, a(n) for n=1..17.

PROG

(PARI) {A277295(n, k) = my(A=x); for(i=1, n, A = x + subst(A^2, x, y*A + (1-y)*x +x*O(x^n)) ); polcoeff(polcoeff(A, n, x), k, y)}

for(n=1, 20, print1(A277295(2*n-1, n-1), ", "))