OFFSET
0,1
LINKS
Jacques Carlier and Corinne Lucet, A decomposition algorithm for network reliability evaluation. In First International Colloquium on Graphs and Optimization (GOI), 1992 (Grimentz). Discrete Appl. Math. 65 (1996), 141-156 (see page 153 and Fig 6).
FORMULA
E.g.f.: 1/2 - exp(x) + 1/2*exp(2*exp(x)-2). a(n-2) = A035009(n)-1. - Ralf Stephan, Jan 26 2004
MATHEMATICA
a[n_] := Sum[Binomial[n, k]*BellB[k, 2], {k, 1, n}]; Table[a[n], {n, 1, 20}] (* Jean-François Alcover, Apr 26 2013 *)
PROG
(PARI) x='x+O('x^66); Vec(serlaplace(1/2-exp(x)+1/2*exp(2*exp(x)-2))) \\ Joerg Arndt, Apr 21 2013
(PARI) a(n) = sum(k=1, n, binomial(n, k)*sum(j=1, k, stirling(k, j, 2)*2^j)); \\ \\ Michel Marcus, Apr 26 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Andre Poenitz (andre.poenitz(AT)mathematik.tu-chemnitz.de)
EXTENSIONS
Added missing digit in the last term from Jean-François Alcover, Apr 26 2013
STATUS
approved