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A203481
a(n) = v(n+1)/(4*v(n)), where v = A203479.
3
1, 20, 1584, 475456, 541981440, 2376277529600, 40580860464967680, 2725519037191790608384, 724680197846400799531008000, 766028090108619425976217272320000, 3227487808644444231639810280103215104000
OFFSET
1,2
LINKS
FORMULA
a(n) = (1/4)*Product_{k=1..n} (2^k + 2^(n+1) - 2). - G. C. Greubel, Aug 28 2023
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^(n+1) +2^k -2, {k, n}]/4, {n, 20}] (* G. C. Greubel, Aug 28 2023 *)
PROG
(Magma) [(&*[2^j + 2^(n+1) - 2: j in [1..n]])/4: n in [1..20]]; // G. C. Greubel, Aug 28 2023
(SageMath) [product(2^j+2^(n+1)-2 for j in range(1, n+1))/4 for n in range(1, 21)] # G. C. Greubel, Aug 28 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Jan 02 2012
STATUS
approved