OFFSET
1,3
EXAMPLE
a(9) = 7 because p#_6 = 30030 < 9! = 362880 < p#_7 = 510510.
MATHEMATICA
Primorial[n_] := Product[ Prime[i], {i, n}]; f[n_] := Block[{k = 1}, While[ Primorial[k] < n!, k++ ]; k]; Table[ f[n], {n, 75}]
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Robert G. Wilson v, Apr 09 2004
STATUS
approved