A092640 Number of consecutive prime runs of 2 primes congruent to 3 mod 4 below 10^n.

0, 5, 20, 101, 751, 5949, 49010, 418366, 3627049, 32067600, 287357618

Offset

1,2

Links

Table of n, a(n) for n=1..11.

Formula

Generate the prime sequence with primes labeled 1 mod 4 or 3 mod 4. Add count of primes to sequence if just 2 primes occur before interruption by a prime congruent to 1 mod 4.

Example

a(4)=101 because 101 pairs of primes occur below 10^4, each run interrupted by a prime congruent to 1 mod 4.

Crossrefs

Cf. A092640, A092641.

Sequence in context: A108509 A110595 A369488 * A165961 A276314 A292358

Adjacent sequences: A092637 A092638 A092639 * A092641 A092642 A092643

Keyword

more,nonn

Author

Enoch Haga, Mar 02 2004

Extensions

a(9)-a(11) from Chai Wah Wu, Mar 18 2018

Status

approved