OFFSET
1,2
COMMENTS
For k > 0, numbers k such that the digits 88 followed by k-1 occurrences of the digit 0 followed by the digit 3 is prime (see Example section).
a(29) > 3*10^5.
LINKS
Makoto Kamada, Factorization of near-repdigit-related numbers.
Makoto Kamada, Search for 880w3.
EXAMPLE
3 is in this sequence because 88*10^3 + 3 = 88003 is prime.
Initial terms and associated primes:
a(1) = 1, 883;
a(2) = 2, 8803;
a(3) = 3, 88003;
a(4) = 7, 880000003;
a(5) = 19, 880000000000000000003, etc.
MATHEMATICA
Select[Range[0, 100000], PrimeQ[88*10^# + 3] &] (* Corrected by Georg Fischer, Jul 22 2019 *)
PROG
(PARI) is(n)=ispseudoprime(88*10^n + 3) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Robert Price, Nov 09 2016
EXTENSIONS
a(28) from Robert Price, May 03 2020
STATUS
approved