A369215 Expansion of (1/x) * Series_Reversion( x * ((1-x)^3-x) ).

1, 4, 29, 261, 2627, 28315, 319648, 3731037, 44663058, 545312504, 6764556591, 85015779095, 1080185111768, 13852183882612, 179058158369828, 2330621446075640, 30519758687849439, 401806204894374041, 5315243189757111099, 70613088335938995385, 941714812929017751855

Offset

0,2

Links

Table of n, a(n) for n=0..20.

Index entries for reversions of series

Formula

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

Prog

(PARI) my(N=30, x='x+O('x^N)); Vec(serreverse(x*((1-x)^3-x))/x)
(PARI) a(n) = sum(k=0, n, binomial(n+k, k)*binomial(4*n+2*k+2, n-k))/(n+1);

Crossrefs

Cf. A369114, A369161.

Cf. A151374, A249924, A369216.

Cf. A049140.

Sequence in context: A254124 A203970 A250885 * A244594 A168238 A370955

Adjacent sequences: A369212 A369213 A369214 * A369216 A369217 A369218

Keyword

nonn

Author

Seiichi Manyama, Jan 16 2024

Status

approved