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.

A354267 A Fibonacci-Pascal triangle read by rows: T(n, n) = 1, T(n, n-1) = n - 1, T(n, 0) = T(n-1, 1) and T(n, k) = T(n-1, k-1) + T(n-1, k) for 0 < k < n-1.

Original entry on oeis.org

1, 0, 1, 1, 1, 1, 1, 2, 2, 1, 2, 3, 4, 3, 1, 3, 5, 7, 7, 4, 1, 5, 8, 12, 14, 11, 5, 1, 8, 13, 20, 26, 25, 16, 6, 1, 13, 21, 33, 46, 51, 41, 22, 7, 1, 21, 34, 54, 79, 97, 92, 63, 29, 8, 1, 34, 55, 88, 133, 176, 189, 155, 92, 37, 9, 1, 55, 89, 143, 221, 309, 365, 344, 247, 129, 46, 10, 1
Offset: 0

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Author

Peter Luschny, May 31 2022

Keywords

Examples

			[0]  1;
[1]  0,  1;
[2]  1,  1,  1;
[3]  1,  2,  2,  1;
[4]  2,  3,  4,  3,  1;
[5]  3,  5,  7,  7,  4,  1;
[6]  5,  8, 12, 14, 11,  5,  1;
[7]  8, 13, 20, 26, 25, 16,  6,  1;
[8] 13, 21, 33, 46, 51, 41, 22,  7, 1;
[9] 21, 34, 54, 79, 97, 92, 63, 29, 8, 1;
		

Crossrefs

Cf. A212804 (first column, which is also row 0 of A352744), A099036 (row sums), A228074 (subtriangle), A000045 (Fibonacci), A371870 (central terms).

Programs

  • Maple
    T := proc(n, k) option remember;
    if n = k then 1 elif k = n-1 then n-1 elif k = 0 then T(n-1, 1) else
    T(n-1, k) + T(n-1, k-1) fi end: seq(seq(T(n, k), k = 0..n), n = 0..11);
  • Mathematica
    T[n_, k_] := Which[n == k, 1, k == n-1, n-1, k == 0, T[n-1, 1], True, T[n-1, k] + T[n-1, k-1]];
    Table[T[n, k], {n, 0, 11}, {k, 0, n}] // Flatten (* Jean-François Alcover, Nov 29 2023 *)
  • Python
    from functools import cache
    @cache
    def A354267row(n):
        if n == 0: return [1]
        if n == 1: return [0, 1]
        row = A354267row(n - 1) + [1]
        s = row[1]
        for k in range(n-1, 0, -1):
            row[k] += row[k - 1]
        row[0] = s
        return row
    for n in range(10): print(A354267row(n))

Formula

T(n, 0) = Fibonacci(n - 1).