1,2

There are 310443 irregular primes less than 12 million.

ip={ the list of irregular primes to 12 million }; NestList[ ip[[ # ]] &, 1, 2]

Cf. A007097.

Sequence in context: A156226 A133998 A056217 this_sequence A140764 A156923 A104180

Adjacent sequences: A105461 A105462 A105463 this_sequence A105465 A105466 A105467

hard,nonn

Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 07 2005