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.

A144287 Square array A(n,k), n>=1, k>=1, read by antidiagonals: A(n,k) = Fibonacci rabbit sequence number n coded in base k.

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 1, 3, 5, 3, 1, 4, 10, 22, 5, 1, 5, 17, 93, 181, 8, 1, 6, 26, 276, 2521, 5814, 13, 1, 7, 37, 655, 17681, 612696, 1488565, 21, 1, 8, 50, 1338, 81901, 18105620, 4019900977, 12194330294, 34, 1, 9, 65, 2457, 289045, 255941280, 1186569930001, 6409020585966267, 25573364166211253, 55
Offset: 1

Views

Author

Alois P. Heinz, Sep 17 2008

Keywords

Examples

			Square array begins:
  1,   1,    1,     1,     1,  ...
  1,   2,    3,     4,     5,  ...
  2,   5,   10,    17,    26,  ...
  3,  22,   93,   276,   655,  ...
  5, 181, 2521, 17681, 81901,  ...
		

Crossrefs

Rows n=1-3 give: A000012, A001477, A002522.
Main diagonal gives A144288.

Programs

  • Maple
    f:= proc(n,b) option remember; `if`(n<2, [n,n], [f(n-1, b)[1]*
           b^f(n-1, b)[2] +f(n-2, b)[1], f(n-1, b)[2] +f(n-2, b)[2]])
        end:
    A:= (n,k)-> f(n,k)[1]:
    seq(seq(A(n, 1+d-n), n=1..d), d=1..11);
  • Mathematica
    f[n_, b_] := f[n, b] = If[n < 2, {n, n}, {f[n-1, b][[1]]*b^f[n-1, b][[2]] + f[n-2, b][[1]], f[n-1, b][[2]] + f[n-2, b][[2]]}]; t[n_, k_] := f[n, k][[1]]; Flatten[ Table[t[n, 1+d-n], {d, 1, 11}, {n, 1, d}]] (* Jean-François Alcover, translated from Maple, Dec 09 2011 *)

Formula

See program.