A114877 - OEIS

%I #18 Mar 04 2023 08:57:16

%S 1,3,125,2100875,2977309629,118890080527911,12677461389063582955701,

%T 7895300107107819831516439618359375,

%U 4725033556599120988065310720798566300246484375

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

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

%t 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 *)

%Y Cf. A114876 (numerators).

%K easy,frac,nonn

%O 1,2

%A _T. D. Noe_, Jan 03 2006

%E Edited by _Michel Marcus_, Mar 04 2023