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A088425 Number of primes in arithmetic progression starting with 17 and with d=2n. 9
2, 1, 3, 1, 1, 4, 2, 1, 1, 2, 1, 2, 2, 1, 2, 1, 1, 3, 1, 1, 3, 2, 1, 1, 2, 1, 2, 2, 1, 1, 2, 1, 3, 1, 1, 2, 1, 1, 1, 2, 1, 2, 2, 1, 3, 2, 1, 2, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 3, 2, 1, 1, 1, 1, 3, 2, 1, 1, 2, 1, 1, 2, 1, 5, 1, 1, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 1, 2, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Arithmetic progression is stopped when next term is not prime. E.g. for n=6 (d=12), a=4, that is 17,29,41,53 are prime, while next term, 65, is not prime.

LINKS

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

MATHEMATICA

bb={}; Do[s=1; Do[If[PrimeQ[17+k*d], s=s+1, bb={bb, s}; Break[]], {k, 10}], {d, 2, 200, 2}]; Flatten[bb]

CROSSREFS

Cf. A088420, A088421, A088422, A088423, A088424, A088426, A088427, A088428, A088429.

Sequence in context: A143349 A335123 A182715 * A141294 A174557 A010766

Adjacent sequences:  A088422 A088423 A088424 * A088426 A088427 A088428

KEYWORD

easy,nonn

AUTHOR

Zak Seidov, Sep 29 2003

STATUS

approved

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Last modified May 7 00:42 EDT 2021. Contains 343609 sequences. (Running on oeis4.)