A152144 An 8th-degree product form sequence: a(n)=Product[(1 + 4*Sin[k*Pi/n]^2 + 16*Sin[k*Pi/n]^4 + 64*Sin[k*Pi/n]^6 + 256*Sin[k*Pi/n]^8), {k, 1, Floor[(n - 1)/2]}].

1, 1, 1, 121, 31, 2501, 605, 51941, 13361, 1176241, 302621, 26454781, 6770555, 590741581, 151200251, 13200630641, 3380212751, 295159215856, 75579365455, 6599238200081, 1689760311371, 147540134993141, 37778247366211

Offset

0,4

Links

Table of n, a(n) for n=0..22.

Mathematica

f[n_] =Product[(1 + 4*Sin[k*Pi/n]^2 + 16*Sin[k*Pi/n]^4 + 64*Sin[k*Pi/n]^6 + 256*Sin[k*Pi/n]^8), {k, 1, Floor[(n - 1)/2]}]; a = Table[f[n], {n, 0, 30}]; Round[a]; FullSimplify[ExpandAll[a]]

Crossrefs

Sequence in context: A014748 A334058 A197817 * A282344 A249627 A202003

Adjacent sequences: A152141 A152142 A152143 * A152145 A152146 A152147

Keyword

nonn

Author

Roger L. Bagula and Gary W. Adamson, Nov 26 2008

Status

approved