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A092636
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Number of consecutive prime runs of 1 prime congruent to 1 mod 4 below 10^n.
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4
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OFFSET
| 1,2
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FORMULA
| Generate the prime sequence with primes labeled 1 mod 4 or 3 mod 4. Add count of primes to sequence if just one prime occurs before interruption by a prime congruent to 3 mod 4.
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EXAMPLE
| a(3)=31 because 31 single primes occur below 10^3, each interrupted in the run by a prime congruent to 3 mod 4.
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PROG
| (PARI) a(n)=my(p=2, q=3, t); forprime(r=5, nextprime(10^n), if(q%4==1&&p%4==3&&r%4==3, t++); p=q; q=r); t \\ Charles R Greathouse IV, Sep 30 2011
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CROSSREFS
| Cf. A091318, A092637-A092665.
Sequence in context: A164038 A084235 A002469 * A178792 A007197 A002649
Adjacent sequences: A092633 A092634 A092635 * A092637 A092638 A092639
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KEYWORD
| more,nonn
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AUTHOR
| Enoch Haga (Enokh(AT)comcast.net), Mar 02 2004
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EXTENSIONS
| a(9) from Charles R Greathouse IV, Sep 30 2011
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