A153436 a(n) is the least k such that k^n*(k^n+1)-1 is prime.
2, 2, 2, 2, 4, 2, 10, 4, 3, 2, 6, 3, 4, 21, 12, 2, 30, 3, 5, 47, 31, 34, 27, 2, 31, 2, 50, 5, 20, 23, 89, 29, 179, 11, 2, 16, 41, 96, 75, 22, 55, 10, 209, 46, 38, 17, 34, 7, 61, 121, 119, 2, 68, 148, 2, 164, 216, 65, 527, 11, 175, 354, 442, 201, 54, 230, 97, 433, 3
Offset: 1
Keywords
Links
- Pierre CAMI, Table of n, a(n) for n = 1..500
Programs
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PARI
a(n) = {my(k=1); while (! isprime(k^n*(k^n+1)-1), k++); k;}
Extensions
Name corrected by Michel Marcus, Sep 24 2019