

A088426


Number of primes in arithmetic progression starting with 19 and with d=2n.


9



1, 2, 1, 1, 2, 3, 1, 1, 2, 1, 2, 3, 1, 2, 1, 1, 2, 1, 1, 2, 3, 1, 1, 2, 1, 2, 4, 1, 1, 4, 1, 2, 1, 1, 2, 1, 1, 1, 2, 1, 2, 2, 1, 2, 3, 1, 2, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 3, 1, 1, 2, 1, 1, 3, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 4, 1, 2, 3, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1
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OFFSET

1,2


COMMENTS

Arithmetic progression is stopped when next term is not prime. E.g. for n=6 (d=12), a=3, that is 19,31,43 are prime, while next term, 55, is not prime.


LINKS

Table of n, a(n) for n=1..100.


MATHEMATICA

bb={}; Do[s=1; Do[If[PrimeQ[19+k*d], s=s+1, bb={bb, s}; Break[]], {k, 10}], {d, 2, 200, 2}]; Flatten[bb]


CROSSREFS

Cf. A088420, A088421, A088422, A088423, A088424, A088425, A088427, A088428, A088429.
Sequence in context: A290695 A277446 A088198 * A124769 A176484 A144328
Adjacent sequences: A088423 A088424 A088425 * A088427 A088428 A088429


KEYWORD

easy,nonn


AUTHOR

Zak Seidov, Sep 29 2003


STATUS

approved



