A071771 Least k > 0 such that the nextprime(k*primorial(n)) - k*primorial(n) is composite.

59, 413, 2018, 48907, 100284, 869700, 23094906, 272703171

Offset: 1

Author

David W. Wilson and Robert G. Wilson v, Jun 04 2002

Keywords

• nonn
• more

Examples

			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.
		

Crossrefs

Cf. A002110, A005235, A071572.

Programs

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}]

Extensions

a(8) from Sean A. Irvine, Aug 08 2024