%I #17 Aug 29 2023 04:24:23

%S 1,4,320,2027520,3855986196480,8359491805553413324800,

%T 79457890145647634305213865656320000,

%U 12897878211365028383150895090566532213003150950400000,140613650417826346093374124598539442743630963394643403845144815232614400000

%N a(n) = Product_{1 <= i < j <= n} (2^i + 2^j - 2).

%C Each term divides its successor, as in A203480.

%H G. C. Greubel, <a href="/A203479/b203479.txt">Table of n, a(n) for n = 1..21</a>

%p a:= n-> mul(mul(2^i+2^j-2, i=1..j-1), j=2..n):

%p seq(a(n), n=1..12); # _Alois P. Heinz_, Jul 23 2017

%t (* First program *)

%t f[j_]:= 2^j -1; z = 15;

%t v[n_]:= Product[Product[f[k] + f[j], {j,k-1}], {k,2,n}]

%t Table[v[n], {n,z}] (* A203479 *)

%t Table[v[n+1]/v[n], {n,z-1}] (* A203480 *)

%t Table[v[n+1]/(4*v[n]), {n,z-1}] (* A203481 *)

%t (* Second program *)

%t Table[Product[2^j +2^k -2, {j,n}, {k,j-1}], {n,15}] (* _G. C. Greubel_, Aug 28 2023 *)

%o (Magma) [(&*[(&*[2^j+2^k-2: k in [1..j]])/(2^(j+1)-2): j in [1..n]]): n in [1..15]]; // _G. C. Greubel_, Aug 28 2023

%o (SageMath) [product(product(2^j+2^k-2 for k in range(1,j)) for j in range(1,n+1)) for n in range(1,16)] # _G. C. Greubel_, Aug 28 2023

%Y Cf. A000225, A093883, A203305, A203480, A203481.

%K nonn

%O 1,2

%A _Clark Kimberling_, Jan 02 2012

%E Name edited by _Alois P. Heinz_, Jul 23 2017