A225941 Smallest k such that k*6^n-1 is prime.
1, 2, 2, 2, 2, 3, 5, 13, 3, 19, 5, 2, 3, 28, 12, 2, 15, 19, 19, 20, 7, 13, 5, 3, 4, 2, 2, 7, 42, 7, 4, 7, 5, 34, 8, 2, 78, 13, 12, 2, 3, 24, 4, 12, 2, 37, 30, 5, 2, 28, 12, 2, 2, 35, 59, 58, 15, 65, 82, 28, 32, 60, 10, 48, 8, 14, 23, 5, 32, 18, 3, 80, 28, 12, 2
Offset: 1
Keywords
Links
- Pierre CAMI, Table of n, a(n) for n = 1..3000
Crossrefs
Cf. A225911.
Programs
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Mathematica
skp[n_]:=Module[{k=1,c=6^n},While[!PrimeQ[k*c-1],k++];k]; Array[skp,80] (* Harvey P. Dale, Jul 22 2013 *) -
PARI
a(n) = my(k=1); while (!isprime(k*6^n-1), k++); k; \\ Michel Marcus, Sep 16 2019
Comments