OFFSET
1,2
COMMENTS
As n increases, a(n) is in average = 0.44*n^2. It appears that 62% of a(n)/n^2 are < 0.44. - Pierre CAMI, Jun 01 2012
LINKS
R. J. Mathar, Table of n, a(n) for n = 1..240
MAPLE
A064215 := proc(n)
for k from 1 do
if isprime(k*6^n-1) and isprime(k*6^n+1) then
return k;
end if;
end do:
end proc: # R. J. Mathar, Sep 17 2015
MATHEMATICA
Table[ k = 1; While[ ! PrimeQ[ k*6^n + 1 ] || ! PrimeQ[ k*6^n - 1 ], k++ ]; k, {n, 50} ]
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Sep 21 2001
STATUS
approved