These numbers are useful for generating intermediate cluster primes because the best algorithm for generating cluster primes requires starting with a known cluster prime.
Table of n, a(n) for n=1..13.
Cf. A038134 (cluster primes), A039506 (number of cluster primes < 10^n), A121045.
Sequence in context: A178006 A053302 A068877 * A107109 A089771 A249448
Adjacent sequences: A121041 A121042 A121043 * A121045 A121046 A121047
T. D. Noe, Jul 21 2006