OFFSET
0,1
LINKS
Robert Israel, Table of n, a(n) for n = 0..1000
FORMULA
a(n)^2-6 = 5^n * A358422(n).
EXAMPLE
a(3) = 359 because 359^2 - 6 = 128875 = 5^3 * 1031 where 359 and 1031 are prime, and no smaller prime works.
MAPLE
f:= proc(n) local v, a, b, k, p, q;
v:= 5^n;
a:= numtheory:-msqrt(6, v);
if a < v/2 then b:= v-a
else b:= a; a:= v-a
fi;
for k from 0 do
for q in [k*v+a, k*v+b] do
if isprime(q) then
p:= (q^2-6)/v;
if isprime(p) then return q fi;
fi
od od
end proc:
map(f, [$0..30]);
CROSSREFS
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, Nov 15 2022
STATUS
approved