OFFSET
1,1
EXAMPLE
For a(2): the second primorial (A002110) is 6. It is not until k = 413, or 6*413 = 2478, that the next prime > 2478 = 2503 less 2478 which equals 25 is a composite.
MATHEMATICA
Do[p = Product[ Prime[i], {i, 1, n}]; k = 1; While[ q = NextPrim[k*p] - k*p; q == 1 || PrimeQ[q], k++ ]; Print[k], {n, 1, 6}]
CROSSREFS
KEYWORD
nonn,more
AUTHOR
David W. Wilson and Robert G. Wilson v, Jun 04 2002
EXTENSIONS
a(8) from Sean A. Irvine, Aug 08 2024
STATUS
approved