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A027496
Cube of the lower triangular normalized 2nd kind Stirling matrix.
6
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
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 A376458 A159252
KEYWORD
nonn,tabl
STATUS
approved