OFFSET
4,1
LINKS
Alois P. Heinz, Table of n, a(n) for n = 4..576
M. Griffiths, I. Mezo, A generalization of Stirling Numbers of the Second Kind via a special multiset, JIS 13 (2010) #10.2.5.
M. Griffiths, Generalized Near-Bell Numbers, JIS 12 (2009) 09.5.7
FORMULA
For n>=4, a(n)=(Bell(n)+6Bell(n-1)+17Bell(n-2)+20Bell(n-3)+21Bell(n-4))/24, where Bell(n) is the n-th Bell number (the Bell numbers are given in A000110). e.g.f. (e^(4x)+12e^(3x)+42e^(2x)+44e^x+21)(e^(e^x-1))/24.
MATHEMATICA
Table[(BellB[n] + 6 BellB[n - 1] + 17 BellB[n - 2] + 20 BellB[n - 3] + 21 BellB[n - 4])/24, {n, 4, 23}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Martin Griffiths, Dec 02 2009
STATUS
approved