1,1

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.

Thanks for the assistance and research of John Moyer. There is likely an infinite number of such primes.

Table of n, a(n) for n=1..25.

a(1)=155921 is prime and it is the only prime between 155900 and 156000.

Cf. A164987.

Sequence in context: A049443 A228473 A156118 * A177811 A341118 A129242

Adjacent sequences: A171655 A171656 A171657 * A171659 A171660 A171661

nonn,base

Ki Punches, Dec 14 2009

Definition detailed and more terms appended - R. J. Mathar, Oct 09 2010

approved