A369190 - OEIS

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A369190

Expansion of (1/x) * Series_Reversion( x / ((1-x)^2 * (1+x)^4) ).

1, 2, 3, -2, -39, -176, -442, -26, 6222, 36062, 113240, 91632, -1303985, -9362520, -34625652, -50327818, 293446186, 2693939308, 11475384425, 23120716658, -62820989127, -813918935104, -3964894957296, -10002153961552, 10192131001136, 250612187843962

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

LINKS

Table of n, a(n) for n=0..25.

Index entries for reversions of series

FORMULA

G.f.: exp( Sum_{k>=1} A368467(k) * x^k/k ).

a(n) = (1/(n+1)) * Sum_{k=0..n} (-1)^k * binomial(2*(n+1),k) * binomial(4*(n+1),n-k).

a(n) = (1/(n+1)) * [x^n] ( (1-x)^2 * (1+x)^4 )^(n+1).

PROG

(PARI) a(n) = sum(k=0, n, (-1)^k * binomial(2*(n+1), k)*binomial(4*(n+1), n-k))/(n+1);