A121292 a(n) = Bell(3*n+1).
1, 15, 877, 115975, 27644437, 10480142147, 5832742205057, 4506715738447323, 4638590332229999353, 6160539404599934652455, 10293358946226376485095653, 21195039388640360462388656799, 52868366208550447901945575624941, 157450588391204931289324344702531067
Offset: 0
Links
- Andrew Howroyd, Table of n, a(n) for n = 0..50
Programs
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Mathematica
Table[ BellB[3*n + 1], {n, 0, 10}] (* Jean-François Alcover, Dec 13 2012 *) -
PARI
a(n)={my(k=3*n+1); k!*polcoef(exp(exp(x + O(x*x^k)) - 1), k)} \\ Andrew Howroyd, Jan 08 2020
Formula
E.g.f.: exp(-1)*Sum_{n>=0} n*exp(n^3*x)/n!.
Extensions
Terms a(11) and beyond from Andrew Howroyd, Jan 08 2020