A100620 Numerator of Cotesian number C(n,0).

0, 1, 1, 1, 7, 19, 41, 751, 989, 2857, 16067, 434293, 1364651, 8181904909, 90241897, 5044289, 15043611773, 5026792806787, 203732352169, 69028763155644023, 1145302367137, 1022779523247467, 396760150748100749, 750218743980105669781, 35200969735190093

Offset

0,5

References

Charles Jordan, Calculus of Finite Differences, Chelsea 1965, p. 513.

Links

Table of n, a(n) for n=0..24.

Example

0, 1/2, 1/6, 1/8, 7/90, 19/288, 41/840, 751/17280, 989/28350, 2857/89600, 16067/598752, 434293/17418240, 1364651/63063000, 8181904909/402361344000, ... = A100620/A100621 = A002177/A002176 (the latter is not in lowest terms)

Maple

(This defines the Cotesian numbers C(n, i)) with(combinat); C:=proc(n, i) if i=0 or i=n then RETURN( (1/n!)*add(n^a*stirling1(n, a)/(a+1), a=1..n+1) ); fi; (1/n!)*binomial(n, i)* add( add( n^(a+b)*stirling1(i, a)*stirling1(n-i, b)/((b+1)*binomial(a+b+1, b+1)), b=1..n-i+1), a=1..i+1); end;

Mathematica

cn[n_, 0] := Sum[n^j*StirlingS1[n, j]/(j + 1), {j, 1, n + 1}]/n!; cn[n_, n_] := cn[n, 0]; cn[n_, k_] := 1/n!*Binomial[n, k]*Sum[n^(j + m)*StirlingS1[k, j]*StirlingS1[n - k, m]/((m + 1)*Binomial[j + m + 1, m + 1]), {m, 1, n}, {j, 1, k + 1}]; Table[cn[n, 0] // Numerator, {n, 0, 24}] (* Jean-François Alcover, Jan 16 2013 *)

Crossrefs

See A002176 for further references. A diagonal of A100640/A100641.

Sequence in context: A097241 A067889 A190821 * A002177 A225279 A192755

Adjacent sequences: A100617 A100618 A100619 * A100621 A100622 A100623

Keyword

nonn,frac

Author

N. J. A. Sloane, Dec 04 2004

Status

approved