OFFSET
0,6
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
B. Chern, P. Diaconis, D. M. Kane, R. C. Rhoades, Closed expressions for averages of set partition statistics, 2013.
MATHEMATICA
Table[(-5 BellB[n+2] + (2 n + 9) BellB[n + 1] + (2 n + 1) BellB[n])/4, {n, 0, 30}] (* Vincenzo Librandi Jul 16 2013 *)
PROG
(PARI) B(n) = if (n<=1, return (1), return (sum(i=0, n-1, binomial(n-1, i)*B(n-1-i))))
a(n) = (-5*B(n+2) + (2*n+9)*B(n+1) + (2*n+1)*B(n))/4
(Magma) [(-5*Bell(n+2)+(2*n+9)*Bell(n+1)+(2*n+1)*Bell(n))/4: n in [0..30]]; // Vincenzo Librandi, Jul 16 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Marcus, Jun 19 2013
STATUS
approved