Generate the prime sequence with primes labeled 1 mod 4 or 3 mod 4. Add count of primes to sequence if just 3 primes occur before interruption by a prime congruent to 1 mod 4.

EXAMPLE

a(5)=323 because 323 sets of 3 primes occur below 10^5, each run interrupted by a prime congruent to 1 mod 4.