A114877 Let d(1)=1 and d(n) = d(n-1)*n^(2n-2)*(2n-1)^(3-2n). Then a(n) = denominator(d(n)).

1, 3, 125, 2100875, 2977309629, 118890080527911, 12677461389063582955701, 7895300107107819831516439618359375, 4725033556599120988065310720798566300246484375

Offset

1,2

Links

Table of n, a(n) for n=1..9.

Example

1, 4/3, 108/125, 442368/2100875, 51200000/2977309629, 52428800000/118890080527911, ...

Mathematica

d[1] = 1; d[n_] := d[n] = d[n - 1]*n^(2 n - 2)*(2 n - 1)^(3 - 2 n); a[n_] := Denominator[d[n]]; Array[a, 10] (* Amiram Eldar, Mar 04 2023 *)

Crossrefs

Cf. A114876 (numerators).

Sequence in context: A037118 A085531 A130614 * A152859 A241647 A157547

Adjacent sequences: A114874 A114875 A114876 * A114878 A114879 A114880

Keyword

easy,frac,nonn

Author

T. D. Noe, Jan 03 2006

Extensions

Edited by Michel Marcus, Mar 04 2023

Status

approved