OFFSET
1,2
COMMENTS
For k > 1, numbers k such that the digit 3 followed by k-2 occurrences of the digit 6 followed by the digits 73 is prime (see Example section).
a(39) > 3*10^5.
LINKS
Makoto Kamada, Search for 36w73.
EXAMPLE
3 is in this sequence because (11*10^3 + 19)/3 = 3673 is prime.
Initial terms and associated primes:
a(1) = 1, 43;
a(2) = 2, 373;
a(3) = 3, 3673;
a(4) = 9, 3666666673;
a(5) = 17, 366666666666666673, etc.
MATHEMATICA
Select[Range[0, 100000], PrimeQ[(11*10^# + 19)/3] &]
PROG
(PARI) is(n)=isprime((11*10^n + 19)/3) \\ Charles R Greathouse IV, Mar 16 2016
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Robert Price, Mar 15 2016
EXTENSIONS
a(37) from Robert Price, Sep 16 2018
a(38) from Robert Price, Jul 25 2024
STATUS
approved