OFFSET
1,2
COMMENTS
For k > 1, numbers k such that the digit 9 followed by k-2 occurrences of the digit 6 followed by the digits 53 is prime (see Example section).
a(31) > 2*10^5.
LINKS
Makoto Kamada, Factorization of near-repdigit-related numbers.
Makoto Kamada, Search for 96w53.
EXAMPLE
5 is in this sequence because (29*10^5 - 41)/3 = 966653 is prime.
Initial terms and associated primes:
a(1) = 1, 83;
a(2) = 2, 953;
a(3) = 5, 966653;
a(4) = 7, 96666653;
a(5) = 13, 96666666666653, etc.
MATHEMATICA
Select[Range[0, 100000], PrimeQ[(29*10^# - 41)/3] &]
PROG
(PARI) lista(nn) = for(n=1, nn, if(ispseudoprime((29*10^n-41)/3), print1(n, ", "))); \\ Altug Alkan, Jul 21 2016
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Robert Price, Jul 21 2016
EXTENSIONS
a(28)-a(30) from Tyler Busby, Mar 20 2024
STATUS
approved