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.

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A173110 Given triangle A173108 = M, then A173110 = Lim_{n->inf.} M^n; the left-shifted vector considered as a sequence.

Original entry on oeis.org

1, 1, 3, 6, 20, 60, 230, 950, 4420, 22230, 120914, 702820, 4343860, 28393280, 195492054
Offset: 0

Views

Author

Gary W. Adamson, Feb 09 2010

Keywords

Comments

Triangle A173108 as an infinite lower triangular matrix * A173110 = A173110;
i.e. the sequence remains unchanged.
Contribution from Gary W. Adamson, Jul 08 2010: (Start)
Let B(x) = (1 + x + 2x^2 + 5x^3 + 15x^4 + ...), Bell numbers, A000110; and
A(x) = (1 + x + 3x^2 + 6x^3 + 20x^4 + ...). Then A(x) = B(x) * B(x^2) *
B(x^4) * B(x^8) * ...; and B(x) = A(x)/A(x^2). (End)

Crossrefs

Cf. A000110 [From Gary W. Adamson, Jul 08 2010]

Formula

Given triangle A173108 = M, then A173110 = Lim_{n->inf.} M^n; the left-shifted vector considered as a sequence

A173108 Triangle, A000110 in every column > 0, shifted down twice.

Original entry on oeis.org

1, 1, 2, 1, 5, 1, 15, 2, 1, 52, 5, 1, 203, 15, 2, 1, 877, 52, 5, 1, 4140, 203, 15, 2, 1, 21147, 877, 52, 5, 1, 115975, 4140, 203, 15, 2, 1, 678570, 21147, 877, 52, 5, 1, 4213597, 115975, 4140, 203, 15, 2, 1, 27644437, 678570, 21147, 877, 52, 5, 1
Offset: 0

Views

Author

Gary W. Adamson, Feb 09 2010

Keywords

Comments

Row sums = A173109: (1, 1, 3, 6, 18, 58, 221, 935, ...).
Let the triangle = M. Then lim_{n->oo} M^n = A173110: (1, 1, 3, 6, 20, 60, ...).

Examples

			First few rows of the triangle:
       1;
       1;
       2,    1;
       5,    1;
      15,    2,   1;
      52,    5,   1;
     203,   15,   2,  1;
     877,   52,   5,  1;
    4140,  203,  15,  2, 1;
   21147,  877,  52,  5, 1;
  115975, 4140, 203, 15, 2, 1;
  ...
		

Crossrefs

Programs

  • Mathematica
    T[n_, k_] := BellB[n - 2 k];
    Table[T[n, k], {n, 0, 10}, {k, 0, Quotient[n, 2]}] // Flatten (* Jean-François Alcover, Apr 22 2022 *)
  • PARI
    B(n) = sum(k=0, n, stirling(n, k, 2)); \\ A000110
    tabf(nn) = for (n=0, nn, for(k=0, n\2, print1(B(n-2*k), ", "));); \\ Michel Marcus, Nov 19 2022

Formula

Bell sequence in every column, for columns > 0, shifted down twice.

Extensions

Keyword tabf and more terms from Michel Marcus, Nov 19 2022
Showing 1-2 of 2 results.