A216568 Smallest k such that prime(n)*k-1 is prime.

2, 1, 4, 2, 4, 8, 4, 2, 6, 6, 2, 2, 4, 6, 6, 4, 6, 8, 6, 4, 14, 2, 4, 16, 2, 10, 6, 6, 6, 6, 6, 4, 4, 2, 10, 12, 2, 6, 10, 4, 10, 8, 22, 8, 4, 2, 2, 8, 4, 2, 16, 6, 14, 12, 12, 4, 6, 2, 12, 4, 6, 4, 2, 10, 6, 6, 2, 2, 6, 8, 10, 6, 2, 6, 2, 4, 6, 6, 22

Offset: 1

Author

Alex Ratushnyak, Sep 19 2012

Keywords

• nonn

Links

• T. D. Noe, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A035096, A034693, A053989.

Programs

Mathematica

Table[k = 1; While[! PrimeQ[Prime[n]*k - 1], k++]; k, {n, 100}] (* T. D. Noe, Sep 19 2012 *)