A069471 Stirling transform of squares of Bell numbers: a(0)=1, a(n) = Sum_{k=1..n} Stirling2(n,k)*(bell(k))^2.

1, 1, 5, 38, 404, 5640, 98769, 2099606, 52883390, 1549218221, 52014755913, 1977659061064, 84305075757125, 3995485979209678, 209005906088572893, 11992147240091361387, 750583356339067110013, 50998365413706734478011

Offset: 0

Author

Karol A. Penson, Mar 25 2002

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 0..250

Crossrefs

Cf. A000110, A001247, A008277.

Programs

Mathematica

Join[{1}, Table[Sum[StirlingS2[n, k]*BellB[k]^2, {k, 1, n}], {n, 1, 50}]] (* G. C. Greubel, May 23 2018 *)