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A027497 4th power of the lower triangular normalized 2nd kind Stirling matrix. 6
1, 15, 1, 4383, 609, 8, 332945, 70127, 1920, 8, 3818466833, 1071459023, 45021783, 392486, 675, 117707753216845145, 41103397063050887, 2332341110766495, 31497752932598, 113377876875, 94910400, 28982153439665068102728041 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..22.

FORMULA

Numerators of lower triangle of (a[ i, j ])^4 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}]; m4 = m.m.m.m; Table[fracs = m4[[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: A027518 A027539 A027479 * A040221 A040220 A146989

Adjacent sequences:  A027494 A027495 A027496 * A027498 A027499 A027500

KEYWORD

nonn,tabl

AUTHOR

Olivier Gérard

STATUS

approved

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Last modified October 4 08:40 EDT 2022. Contains 357239 sequences. (Running on oeis4.)