A027496 Cube of the lower triangular normalized 2nd kind Stirling matrix.

1, 7, 1, 379, 117, 4, 8887, 4297, 312, 4, 3634247, 2411993, 273657, 7418, 45, 512080090549, 435104283499, 67806664899, 2877230158, 36766575, 121680, 267019057484932787, 278169352029443501, 55479403017630012

Offset

1,2

Links

Table of n, a(n) for n=1..24.

Formula

Numerators of lower triangle of (a[ i, j ])^3 where a[ i, j ] = S(i, j)/BellNumber(i) if j<=i, 0 if j>i

Mathematica

rows = 7; m = Table[If[k <= n, StirlingS2[n, k]/BellB[n], 0], {n, 1, rows}, {k, 1, rows}]; m3 = m.m.m; Table[fracs = m3[[i]]; nums = fracs // Numerator; dens = fracs // Denominator; lcm = LCM @@ dens; Table[nums[[j]]*lcm/dens[[j]], {j, 1, i}], {i, 1, rows}] // Flatten (* Jean-François Alcover, Mar 05 2013 *)

Crossrefs

Cf. A008277.

Sequence in context: A027478 A009792 A103243 * A056009 A159252 A357389

Adjacent sequences: A027493 A027494 A027495 * A027497 A027498 A027499

Keyword

nonn,tabl

Author

Olivier Gérard

Status

approved