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.

A145149 7th column of A145142.

Original entry on oeis.org

1, 28, 546, 9450, 165693, 3065238, 59919431, 1226978753, 26377959608, 598190993400, 14328713682920, 361513209493800, 9581318478006976, 266382420824204560, 7761376103890530800, 236610865058490439440, 7532969497593532001856, 250026557590986469841856
Offset: 8

Views

Author

Alois P. Heinz, Oct 03 2008

Keywords

Crossrefs

Cf. A145153.

Programs

  • Maple
    row:= proc(n) option remember; local f,i,x; f:= unapply (simplify (sum ('cat (a||i) *x^i', 'i'=0..n-1) ), x); unapply (subs (solve ({seq(f(i+1)= coeftayl (x/ (1-x-x^4)/ (1-x)^i, x=0, n), i=0..n-1)}, {seq (cat (a||i), i=0..n-1)}), sum ('cat (a||i) *x^i', 'i'=0..n-1) ), x); end: a:= n-> `if` (n=0, 0, coeftayl (row(n)(x), x=0, 7) *(n-1)!): seq (a(n), n=8..26);
  • Mathematica
    row[n_] := row[n] = Module[{f, i, x, a}, f = Function[Sum[a[i]*#^i, {i, 0, n-1}]]; Function[x, Sum[a[i]*x^i, {i, 0, n-1}] /. First @ Solve[Table[f[i+1] == SeriesCoefficient[x/(1-x-x^4)/(1-x)^i, {x, 0, n}], {i, 0, n-1}]]]]; a[n_] := If[n == 0, 0, SeriesCoefficient[row[n][x], {x, 0, 7}]*(n-1)!]; Table[a[n], {n, 8, 26}] (* Jean-François Alcover, Feb 13 2014, after Maple *)

Extensions

More terms from Vincenzo Librandi, Feb 15 2014