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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A114607 Start with 1 0 1 0 then add a one every time (e.g. 1 1 0 1 1 1 0 1 1 1 1 0 ...).

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
Offset: 1

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Author

Dan M. Smith (SmittyDa33(AT)yahoo.com), Dec 14 2005

Keywords

Crossrefs

Cf. A073424.
Essentially the same sequence as A023532 and A123110. - N. J. A. Sloane, Feb 07 2020

Programs

  • Mathematica
    Flatten[Join[{1,0},Table[Join[PadRight[{},n,1],{0}],{n,20}]]] (* Harvey P. Dale, Dec 23 2012 *)

Formula

a(n)=A023532(n-2), n>1. [From R. J. Mathar, Aug 11 2008]

A385895 Table read by rows: T(n, k) = T(n, k-1) + m * T(n-1, n-k) for k > 1, T(n, 1) = T(n-1, n-1), and T(n, 0) = 0^n, for m = 2.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 1, 3, 3, 0, 3, 9, 11, 11, 0, 11, 33, 51, 57, 57, 0, 57, 171, 273, 339, 361, 361, 0, 361, 1083, 1761, 2307, 2649, 2763, 2763, 0, 2763, 8289, 13587, 18201, 21723, 23889, 24611, 24611, 0, 24611, 73833, 121611, 165057, 201459, 228633, 245211, 250737, 250737
Offset: 0

Views

Author

Peter Luschny, Jul 20 2025

Keywords

Comments

The sequence extends the generalized Euler numbers A001586 to a regular table by a parametrized Seidel transformation (see the Python program) that for the case m = 1 leads to the Euler-Bernoulli numbers A008281.

Examples

			Triangle begins:
  [0] 1;
  [1] 0,    1;
  [2] 0,    1,    1;
  [3] 0,    1,    3,     3;
  [4] 0,    3,    9,    11,    11;
  [5] 0,   11,   33,    51,    57,    57;
  [6] 0,   57,  171,   273,   339,   361,   361;
  [7] 0,  361, 1083,  1761,  2307,  2649,  2763,  2763;
  [8] 0, 2763, 8289, 13587, 18201, 21723, 23889, 24611, 24611;
		

Crossrefs

Cf. A001586 (main diagonal), A123110 (m=0), A008281 (m=1), this sequence (m=2).

Programs

  • Maple
    T := proc(n, k) option remember; ifelse(k = 0, 0^n, ifelse(k = 1, T(n-1, n-1), T(n, k-1) + 2*T(n-1, n-k))) end: seq(seq(T(n, k), k = 0..n), n = 0..9);
  • Mathematica
    T[n_, k_] := T[n, k] =
      Which[
        k == 0, Boole[n == 0],
        k == 1, T[n - 1, n - 1],
        True, T[n, k - 1] + 2*T[n - 1, n - k]
      ];
    Table[T[n, k], {n, 0, 8}, {k, 0, n}] // Flatten
  • Python
    from functools import cache
    @cache
    def seidel(n: int, m: int) -> list[int]:
        if n == 0: return [1]
        rowA = seidel(n - 1, m)
        row = [0] + rowA
        row[1] = row[n]
        for k in range(2, n + 1):
            row[k] = row[k - 1] + m * rowA[n - k]
        return row
    def A385895row(n: int) -> list[int]: return seidel(n, 2)
    for n in range(9): print(A385895row(n))
Previous Showing 11-12 of 12 results.