

A326230


Least k > 1 such that k^n is a twin rank (cf. A002822: 6*k^n + 1 are twin primes).


7



2, 5, 28, 70, 2, 1820, 110, 1850, 2520, 220, 2023, 9415, 647, 2880, 2562, 3895, 2, 51240, 525, 3750, 147, 2350, 355, 4480, 2588, 3370, 38157, 1185, 1473, 12530, 4338, 1540, 1988, 535, 102, 22606, 13773, 18895, 16373, 2635, 20428, 76300, 23037, 29005, 11078
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OFFSET

1,1


COMMENTS

Dinculescu observes that when k^2 > 1 is a twin rank (i.e., in A002822) then 5  k (k is divisible by 5), and if k^3 is a twin rank, then 7  k; cf. A326232 & A326234. It is unknown whether there are other pairs (a, b) such that a  n whenever n^b > 1 is a twin rank. (Of course 2  b => 5  a and 3  b => 7  a, so we aren't interested in pairs (a, b) which are consequence of this.)


LINKS



PROG

(PARI) a(n)=for(k=2, oo, ispseudoprime(6*k^n1)&&ispseudoprime(6*k^n+1)&&return(k))


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



