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.

A185813 Riordan array (A000045(x), x*A005043(x)).

Original entry on oeis.org

0, 1, 0, 1, 1, 0, 2, 1, 1, 0, 3, 3, 1, 1, 0, 5, 5, 4, 1, 1, 0, 8, 11, 7, 5, 1, 1, 0, 13, 22, 18, 9, 6, 1, 1, 0, 21, 48, 39, 26, 11, 7, 1, 1, 0, 34, 106, 94, 59, 35, 13, 8, 1, 1, 0, 55, 245, 223, 152, 82, 45, 15, 9, 1, 1, 0
Offset: 0

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Author

Vladimir Kruchinin, Feb 05 2011

Keywords

Examples

			Array begins:
   0;
   1,   0;
   1,   1,   0;
   2,   1,   1,   0;
   3,   3,   1,   1,  0;
   5,   5,   4,   1,  1,  0;
   8,  11,   7,   5,  1,  1,  0;
  13,  22,  18,   9,  6,  1,  1, 0;
  21,  48,  39,  26, 11,  7,  1, 1, 0;
  34, 106,  94,  59, 35, 13,  8, 1, 1, 0;
  55, 245, 223, 152, 82, 45, 15, 9, 1, 1, 0;
		

Crossrefs

Cf. A000045 (Fibonacci).

Programs

  • Maple
    A185813 := proc(n,k) if n = k then 0; elif k = 0 then combinat[fibonacci](n) ; else k*add(1/(n-i)*combinat[fibonacci](i)*add(binomial(2*j-k-1,j-1) *(-1)^(n-j-i) *binomial(n-i,j),j=k..n-i),i=0..n-k) ; end if; end proc:
    seq(seq(A185813(n,k),k=0..n),n=0..15) ; # R. J. Mathar, Feb 10 2011
  • Mathematica
    r[n_, k_] := k*Sum[((-1)^(n+k-i)*Fibonacci[i]*(n-i)!*HypergeometricPFQ[{k/2 + 1/2, k/2, i+k-n}, {k, k+1}, 4])/((n-i)*k!*(n-i-k)!), {i, 0, n-k}]; r[n_, 0] := Fibonacci[n]; Table[r[n, k], {n, 0, 10}, {k, 0, n}] // Flatten (* Jean-François Alcover, Feb 21 2013 *)

Formula

R(n,k) = k*Sum_{i=0..(n-k)} Fibonacci(i)*(Sum_{j=k..(n-i)} binomial(2*j-k-1,j-1)*(-1)^(n-j-i)*binomial(n-i,j))/(n-i), k>1.
R(n,0) = Fibonacci(n).