|
|
A051130
|
|
Indices of prime Bell numbers A000110.
|
|
10
|
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Bell(2841) has been certified to be a prime using Primo. This took 17 months on a P3-800, a P4-2400 and finally a P4-2800. There are no other terms below 6000. - Ignacio Larrosa Cañestro, Feb 13 2004
|
|
LINKS
|
|
|
EXAMPLE
|
The Bell numbers Bell(2)=2, Bell(3)=5, Bell(7)=877 etc. are primes.
|
|
MATHEMATICA
|
Reap[For[n = 1, n <= 3000, n++, If[PrimeQ[BellB[n]], Print[n]; Sow[n]]]][[2, 1]] (* Jean-François Alcover, Jun 05 2012 *)
Select[Range[2900], PrimeQ[BellB[#]]&] (* Harvey P. Dale, Nov 08 2012 *)
|
|
PROG
|
|
|
CROSSREFS
|
|
|
KEYWORD
|
hard,nonn,nice
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|