OFFSET
2,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 2..200
W. M. B. Dukes, Tables of matroids.
W. M. B. Dukes, Counting and Probability in Matroid Theory, Ph.D. Thesis, Trinity College, Dublin, 2000.
W. M. B. Dukes, On the number of matroids on a finite set, arXiv:math/0411557 [math.CO], 2004.
FORMULA
G.f.: Sum_{k > 1} x^k / ((1 - x) * (1 - x^2) * ... * (1 - x^k)). - Michael Somos, Feb 26 2014
E.g.f.: exp(exp(x) - 1) - exp(x). - Ilya Gutkovskiy, Feb 08 2020
EXAMPLE
G.f. = x^2 + 4*x^3 + 14*x^4 + 51*x^5 + 202*x^6 + 876*x^7 + 4139*x^8 + ...
MATHEMATICA
Table[BellB[n, 1] - 1, {n, 2, 23}] (* Zerinvary Lajos, Jul 16 2009 *)
PROG
(Magma) [Bell(n)-1: n in [2..30]]; // Vincenzo Librandi, Mar 04 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 30 2000
STATUS
approved