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.

A152972 A vector sequence with set row sum function: row(n)=-Product[3*k - 1, {k, 0, n}] and linear build up and decline function: f(n,m)=Floor[(m/n)*row(n)].

Original entry on oeis.org

1, 1, 1, 1, 8, 1, 1, 39, 39, 1, 1, 110, 658, 110, 1, 1, 1232, 4927, 4927, 1232, 1, 1, 17453, 34906, 104720, 34906, 17453, 1, 1, 299200, 598400, 1196799, 1196799, 598400, 299200, 1, 1, 6021400, 12042800, 18064200, 24085598, 18064200, 12042800
Offset: 0

Views

Author

Roger L. Bagula, Dec 16 2008

Keywords

Comments

row sums -Product[3*k - 1, {k, 0, n}]:A008544
{1, 2, 10, 80, 880, 12320, 209440, 4188800, 96342400, 2504902400, 72642169600,
2324549427200, 81359229952000, 3091650738176000, 126757680265216000,
5577337931669504000, 262134882788466688000, 13106744139423334400000,
694657439389436723200000,...}

Examples

			{1},
{1, 1},
{1, 8, 1},
{1, 39, 39, 1},
{1, 110, 658, 110, 1},
{1, 1232, 4927, 4927, 1232, 1},
{1, 17453, 34906, 104720, 34906, 17453, 1},
{1, 299200, 598400, 1196799, 1196799, 598400, 299200, 1},
{1, 6021400, 12042800, 18064200, 24085598, 18064200, 12042800, 6021400, 1},
{1, 139161244, 278322488, 417483733, 417483734, 417483734, 417483733, 278322488, 139161244, 1},
{1, 3632108480, 7264216960, 10896325440, 14528433920, -2, 14528433920, 10896325440, 7264216960, 3632108480, 1}
		

Crossrefs

Programs

  • Mathematica
    Clear[v, n, row, f]; row[n_] = -Product[3*k - 1, {k, 0, n}];
    f[n_, m_] = Floor[(m/n)*row[n]/2]; v[0] = {1}; v[1] = {1, 1};
    v[n_] := v[n] = If[Mod[n, 2] == 0, Join[{1}, Table[ f[n, m], {m, 1, Floor[ n/2] - 1}], {row[n] - 2*Sum[ f[n, m], {m, 1, Floor[n/2] - 1}] - 2}, Table[ f[n, m], {m, Floor[n/ 2] - 1, 1, -1}], { 1}],
    Join[{1}, Table[ f[n, m], {m, 1, Floor[n/2] - 1}], {row[n]/2 - Sum[ f[n, m], { m, 1, Floor[n/2] - 1}] - 1, row[n]/ 2 - Sum[ f[n, m], {m, 1, Floor[ n/2] - 1}] - 1}, Table[ f[n, m], {m, Floor[n/ 2] - 1, 1, -1}], {1}]];
    Table[FullSimplify[v[n]], {n, 0, 10}]; Flatten[%]

Formula

row(n)=(2*n)!/n!: f(n,m)=Floor[(m/n)*row(n)].