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.

A195009 Triangle read by rows, T(n,k) = k^n*A056040(n), n>=0, 0<=k<=n.

Original entry on oeis.org

1, 0, 1, 0, 2, 8, 0, 6, 48, 162, 0, 6, 96, 486, 1536, 0, 30, 960, 7290, 30720, 93750, 0, 20, 1280, 14580, 81920, 312500, 933120, 0, 140, 17920, 306180, 2293760, 10937500, 39191040, 115296020, 0, 70, 17920, 459270, 4587520, 27343750, 117573120, 403536070, 1174405120
Offset: 0

Views

Author

Peter Luschny, Sep 07 2011

Keywords

Examples

			                     1
                    0, 1
                  0, 2, 8
               0, 6, 48, 162
            0, 6, 96, 486, 1536
       0, 30, 960, 7290, 30720, 93750
0, 20, 1280, 14580, 81920, 312500, 933120
		

Programs

  • Maple
    swing := n -> n!/iquo(n,2)!^2: pow := (n,k) -> if k=0 and n=0 then 1 else n^k fi: A195009 := (n,k) -> pow(k,n)*swing(n):
    # Formula:
    omega := proc(x) BesselI(0,2*m*x)+(2*m*x+1)*BesselI(1,2*m*x) end:
    f := n -> `if`(irem(n,2)=1,(n+1)/2,1/(n+1)): A195009 := proc(n,k)
    limit(f(n)*(D@@n)(omega)(x),x=0); subs(m=k,%) end;
  • Mathematica
    sf[n_] := With[{f = Floor[n/2]}, Pochhammer[f+1, n-f]/f!]; t[0, 0] = 1; t[n_, k_] := k^n*sf[n]; Table[t[n, k], {n, 0, 8}, {k, 0, n}] // Flatten (* Jean-François Alcover, Jul 29 2013 *)

Formula

T(n,k) = f(n)*lim(x=0, (d^n/dx)(BesselI(0,2*k*x)+(2*k*x+1) *BesselI(1,2*k*x) where f(n) = (n+1)/2 if n is odd, 1/(n+1) otherwise.