OFFSET
1,6
FORMULA
Generate the prime sequence with primes labeled 1 mod 4 or 3 mod 4. Add count of primes to sequence if just 9 primes occur before interruption by a prime congruent to 3 mod 4.
EXAMPLE
a(6)=6 because 6 sets of 9 primes occur below 10^6, each run interrupted by a prime congruent to 3 mod 4.
CROSSREFS
KEYWORD
more,nonn
AUTHOR
Enoch Haga, Mar 02 2004
EXTENSIONS
a(9) from Rick L. Shepherd, Jul 15 2009
a(10) from Sean A. Irvine, Oct 25 2011
a(11) from Chai Wah Wu, Mar 18 2018
STATUS
approved