OFFSET
0,6
COMMENTS
Conjecture: for all n, a(n)>0.
PROG
(PARI) a(n) = {k = 0; while (! isprime(eval(concat(Str(2^n), Str((10^k-1)/3)))), k++); k; } \\ Michel Marcus, Sep 16 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, Sep 14 2014
EXTENSIONS
More terms from Michel Marcus, Sep 16 2014
STATUS
approved