%I #11 Jan 03 2022 20:43:01
%S 155921,5649221,6726821,8598221,8825321,9953621,10303721,11948021,
%T 12117121,14645921,14821721,14866421,15275021,17270621,17524921,
%U 18497321,19193921,19731821,20741621,21721621,22170221,23009521,24257921,24579221,24919721
%N Primes ending with the digits 21 which are the only primes in their century.
%C Primes of the form 100*k+21 with no other prime of the form 100*k+j for j=1 to 99 with the same k.
%C Thanks for the assistance and research of John Moyer. There is likely an infinite number of such primes.
%e a(1)=155921 is prime and it is the only prime between 155900 and 156000.
%Y Cf. A164987.
%K nonn,base
%O 1,1
%A _Ki Punches_, Dec 14 2009
%E Definition detailed and more terms appended by _R. J. Mathar_, Oct 09 2010
