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.

A006209 Generalized Fibonacci numbers A_{n,4}.

Original entry on oeis.org

1, 1, 0, 1, 0, 2, 0, 3, 1, 6, 2, 9, 4, 18, 8, 30, 16, 56, 32, 101, 64, 191, 128, 351, 256, 668, 512, 1257, 1026, 2402, 2056, 4592, 4122, 8854, 8272, 17092, 16608, 33212, 33364, 64674, 67072, 126490, 134912, 248038, 271528, 487986, 546818, 962350
Offset: 1

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Author

Keywords

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A006206 (A_{n,1}), A006207 (A_{n,2}), A006208 (A_{n,3}), A130628 (A_{n,5}), A208092 (A_{n,6}), A006210 (D_{n,2}), A006211 (D_{n,3}), A094392.

Programs

  • Mathematica
    max = 100; Clear[b1, b2];
    For[n = 1, n <= max, n++,
    For[j = 1, j <= n, j++, b1[1][j, n] = 0; b1[2][j, n] = 1; b2[1][j, n] = b2[2][j, n] = 0];
    b2[1][n, n] = b2[2][n, n] = 1];
    For[k = 3, k <= max, k++,
    For[n = 1, n <= max, n++,
    For[j = 1, j <= n-1, j++, b1[k][j, n] = b1[k-2][1, n] + b1[k-2][j+1, n]; b2[k][j, n] = b2[k-2][1, n] + b2[k-2][j+1, n]];
    b1[k][n, n] = b1[k-2][1, n] + b1[k-1][n, n]; b2[k][n, n] = b2[k-2][1, n] + b2[k-1][n, n]
    ]];
    phin[n_] := Table[b2[m][n, n] + 2 Sum[If[m + 2 - 2 j > 0, b1[m + 2 - 2j][j, n], 0], {j, 1, n}], {m, 1, max}];
    MT[s_List] := Table[DivisorSum[n, MoebiusMu[#] s[[n/#]]&]/n, {n, 1, Length[s]}];
    MT[phin[4]] (* Jean-François Alcover, Nov 05 2018, adapted from Max Alekseyev's PARI script *)
  • PARI
    \\ implementation of MT() and phin() is given in A006207
    MT(phin(4)) \\ sequence A_{n,4} \\ Max Alekseyev, Feb 23 2012

Extensions

Terms a(32) onward from Max Alekseyev, Feb 23 2012