cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A152036 Triangular product sequence based 2^n times the Fibonacci version and 4 replaced with m: t(m,n)=2^n*Product[(1 + m*Cos[k*Pi/n]^2), {k, 1, Floor[(n - 1)/2]}].

Original entry on oeis.org

1, 1, 2, 1, 2, 4, 1, 2, 4, 14, 1, 2, 4, 16, 48, 1, 2, 4, 18, 56, 202, 1, 2, 4, 20, 64, 248, 880, 1, 2, 4, 22, 72, 298, 1100, 4286, 1, 2, 4, 24, 80, 352, 1344, 5504, 21760, 1, 2, 4, 26, 88, 410, 1612, 6914, 28336, 118898, 1, 2, 4, 28, 96, 472, 1904, 8528, 36096, 157472
Offset: 0

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Author

Roger L. Bagula and Gary W. Adamson, Nov 20 2008

Keywords

Comments

The row sums are: {1, 3, 7, 21, 71, 283, 1219, 5785, 29071, 156291, 880507,...}. A sequence of sequences with the row numbers m instead of n: and the ratio increases with each row: at (1+Sqrt[5]) for m=4.

Examples

			1;
1, 2;
1, 2, 4;
1, 2, 4, 14;
1, 2, 4, 16, 48;
1, 2, 4, 18, 56, 202;
1, 2, 4, 20, 64, 248, 880;
1, 2, 4, 22, 72, 298, 1100, 4286;
1, 2, 4, 24, 80, 352, 1344, 5504, 21760;
1, 2, 4, 26, 88, 410, 1612, 6914, 28336, 118898;
1, 2, 4, 28, 96, 472, 1904, 8528, 36096, 157472, 675904;
		

Crossrefs

Cf. A103435 (row 4), A083694 (row 5)

Programs

  • Mathematica
    f[n_, m_] = 2^n*Product[(1 + m*Cos[k*Pi/n]^2), {k, 1, Floor[(n - 1)/2]}]; Table[Table[FullSimplify[ExpandAll[f[n, m]]], {n, 0, m}], {m, 0, 10}]

Formula

t(m,n)=2^n*Product[(1 + m*Cos[k*Pi/n]^2), {k, 1, Floor[(n - 1)/2]}].