A291285 Expansion of G(x)^4 where G(x) = g.f. for A291096.

1, 12, 198, 3780, 78489, 1721412, 39234780, 920140884, 22059787860, 538209747504, 13319611953102, 333555996632508, 8436806028184590, 215223666947011800, 5530993034609017080, 143057705860198877940, 3721183384198820225004, 97282669559237767849104

Offset

0,2

Links

Alois P. Heinz, Table of n, a(n) for n = 0..690

Valentin Bonzom, Luca Lionni, Counting Gluings of Octahedra, Electronic Journal of Combinatorics 24(3) (2017), #P3.36. See Eq. (47).

Formula

a(n) ~ 2^(8*n+17/2) / (sqrt(Pi) * n^(3/2) * 3^(2*n+9/2)). - Vaclav Kotesovec, Aug 26 2017

Maple

a:= proc(n) option remember; `if`(n=0, 1, a(n-1)*8*
      (4*n+1)*(2*n+1)*(4*n+3)/((3*n+2)*(3*n+4)*(n+1)))
    end:
seq(a(n), n=0..20);  # Alois P. Heinz, Aug 26 2017

Crossrefs

Cf. A291096.

Sequence in context: A321033 A048667 A115865 * A159359 A119864 A036240

Adjacent sequences: A291282 A291283 A291284 * A291286 A291287 A291288

Keyword

nonn

Author

N. J. A. Sloane, Aug 26 2017

Extensions

More terms from Alois P. Heinz, Aug 26 2017

Status

approved