A092646 - OEIS

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A092646

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

0, 0, 1, 15, 111, 1013, 8963, 78496, 703783, 6388533 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,4`
	FORMULA	`Generate the prime sequence with primes labeled 1 mod 4 or 3 mod 4. Add count of primes to sequence if just 4 primes occur before interruption by a prime congruent to 1 mod 4.`
	EXAMPLE	`a(5)=111 because 111 sets of 4 primes occur below 10^5, each run interrupted by a prime congruent to 1 mod 4.`
	MATHEMATICA	`p1 = p3 = 0; p = 15; s = Mod[{2, 3, 5, 7, 11, 13}, 4]; Do[ While[p < 10^n, If[s == {3, 1, 1, 1, 1, 3}, p1++]; If[s == {1, 3, 3, 3, 3, 1}, p3++]; p = NextPrime@ p; s = Join[ Take[s, -5], {Mod[p, 4]}]]; Print[{p1, p3}], {n, 2, 9}] (* Robert G. Wilson v, 30 Sept 2011 *)`
	CROSSREFS	`Cf. A092645 A092647.` `Sequence in context: A054367 A199225 A034184 * A105040 A105051 A110822` `Adjacent sequences: A092643 A092644 A092645 * A092647 A092648 A092649`
	KEYWORD	`more,nonn`
	AUTHOR	`Enoch Haga (Enokh(AT)comcast.net), Mar 02 2004`

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Last modified February 17 09:41 EST 2012. Contains 206009 sequences.