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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A346415 Triangle T(n,k), n>=0, 0<=k<=n, read by rows, where column k is (1/k!) times the k-fold exponential convolution of Fibonacci numbers with themselves.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 2, 3, 1, 0, 3, 11, 6, 1, 0, 5, 35, 35, 10, 1, 0, 8, 115, 180, 85, 15, 1, 0, 13, 371, 910, 630, 175, 21, 1, 0, 21, 1203, 4494, 4445, 1750, 322, 28, 1, 0, 34, 3891, 22049, 30282, 16275, 4158, 546, 36, 1, 0, 55, 12595, 107580, 202565, 144375, 49035, 8820, 870, 45, 1
Offset: 0

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Author

Alois P. Heinz, Jul 15 2021

Keywords

Comments

The sequence of column k>0 satisfies a linear recurrence with constant coefficients of order k+1.

Examples

			Triangle T(n,k) begins:
  1;
  0,  1;
  0,  1,     1;
  0,  2,     3,      1;
  0,  3,    11,      6,      1;
  0,  5,    35,     35,     10,      1;
  0,  8,   115,    180,     85,     15,     1;
  0, 13,   371,    910,    630,    175,    21,    1;
  0, 21,  1203,   4494,   4445,   1750,   322,   28,   1;
  0, 34,  3891,  22049,  30282,  16275,  4158,  546,  36,  1;
  0, 55, 12595, 107580, 202565, 144375, 49035, 8820, 870, 45, 1;
  ...
		

Crossrefs

Columns k=0-4 give: A000007, A000045, A014335, A014337, A014341.
T(n+j,n) for j=0-2 give: A000012, A000217, A000914.
Row sums give A256180.

Programs

  • Maple
    b:= proc(n) option remember; `if`(n=0, 1, add(expand(x*b(n-j)
          *binomial(n-1, j-1)*(<<0|1>, <1|1>>^j)[1, 2]), j=1..n))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=0..n))(b(n)):
    seq(T(n), n=0..12);
    # second Maple program:
    b:= proc(n, k) option remember; `if`(k=0, 0^n, `if`(k=1,
           combinat[fibonacci](n), (q-> add(binomial(n, j)*
           b(j, q)*b(n-j, k-q), j=0..n))(iquo(k, 2))))
        end:
    T:= (n, k)-> b(n, k)/k!:
    seq(seq(T(n, k), k=0..n), n=0..12);
  • Mathematica
    b[n_, k_] := b[n, k] = If[k == 0, 0^n, If[k == 1, Fibonacci[n], With[{q = Quotient[k, 2]}, Sum[Binomial[n, j] b[j, q] b[n-j, k-q], {j, 0, n}]]]];
    T[n_, k_] := b[n, k]/k!;
    Table[Table[T[n, k], {k, 0, n}], {n, 0, 12}] // Flatten (* Jean-François Alcover, Nov 06 2021, after 2nd Maple program *)

A014340 Four-fold exponential convolution of Fibonacci numbers with themselves.

Original entry on oeis.org

0, 0, 0, 0, 24, 240, 2040, 15120, 106680, 726768, 4861560, 32126160, 210749880, 1375923120, 8955795576, 58177326480, 377439735480, 2446686537840, 15851581501560, 102662600100432, 664738663537080
Offset: 0

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Author

Keywords

Crossrefs

Cf. A000045.

Formula

(1/25){4^n[F(n)+2F(n-1)] + 2[F(3n-2)-3F(3n+1)] + 6*2^n}, F(n)=A000045(n). - Ralf Stephan, May 14 2004
G.f.:(-24*x^4)/((2*x-1)*(16*x^2+4*x-1)*(x^2+4*x-1)) [From Maksym Voznyy (voznyy(AT)mail.ru), Jul 26 2009]
a(n) = 24*A014341(n).
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