OFFSET
1,3
COMMENTS
Also numbers k such that (2*10^k + 43)/9 is prime.
a(11) > 50000. - Robert Price, Oct 27 2014
LINKS
FORMULA
a(n) = A056677(n-1) + 1.
MATHEMATICA
Do[ If[ PrimeQ[ 2(10^n - 1)/9 + 5], Print[n]], {n, 0, 5000}]
PROG
(Magma) [n: n in [0..1000] | IsPrime( 2*(10^n - 1) div 9 + 5)]; // Vincenzo Librandi, Oct 28 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Oct 14 2004
EXTENSIONS
Added a(1)=0, adapted Mathematica program, Vincenzo Librandi, Oct 28 2014
a(11)-a(12) from Kamada data by Tyler Busby, May 03 2024
STATUS
approved