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A203479
a(n) = Product_{1 <= i < j <= n} (2^i + 2^j - 2).
4
1, 4, 320, 2027520, 3855986196480, 8359491805553413324800, 79457890145647634305213865656320000, 12897878211365028383150895090566532213003150950400000, 140613650417826346093374124598539442743630963394643403845144815232614400000
OFFSET
1,2
COMMENTS
Each term divides its successor, as in A203480.
LINKS
MAPLE
a:= n-> mul(mul(2^i+2^j-2, i=1..j-1), j=2..n):
seq(a(n), n=1..12); # Alois P. Heinz, Jul 23 2017
MATHEMATICA
(* First program *)
f[j_]:= 2^j -1; z = 15;
v[n_]:= Product[Product[f[k] + f[j], {j, k-1}], {k, 2, n}]
Table[v[n], {n, z}] (* A203479 *)
Table[v[n+1]/v[n], {n, z-1}] (* A203480 *)
Table[v[n+1]/(4*v[n]), {n, z-1}] (* A203481 *)
(* Second program *)
Table[Product[2^j +2^k -2, {j, n}, {k, j-1}], {n, 15}] (* G. C. Greubel, Aug 28 2023 *)
PROG
(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
(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
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Jan 02 2012
EXTENSIONS
Name edited by Alois P. Heinz, Jul 23 2017
STATUS
approved