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 A088422 Number of primes in arithmetic progression starting with 7 and with d=2n. 9
 1, 2, 3, 1, 2, 4, 1, 2, 1, 1, 2, 2, 1, 1, 6, 1, 2, 3, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 1, 3, 1, 2, 3, 1, 1, 4, 1, 2, 1, 1, 2, 1, 1, 1, 2, 1, 2, 3, 1, 2, 4, 1, 2, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 2, 3, 1, 1, 1, 1, 2, 2, 1, 1, 7, 1, 1, 2, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 3, 1, 2, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Arithmetic progression is stopped when next term is not prime. E.g. for n=3, a=3, that is 7,13,19 are prime, while next term, 25, is not prime. LINKS MATHEMATICA bb={}; Do[s=1; Do[If[PrimeQ[7+k*d], s=s+1, bb={bb, s}; Break[]], {k, 10}], {d, 2, 200, 2}]; Flatten[bb] CROSSREFS Cf. A088420, A088421, A088423, A088424, A088425, A088426, A088427, A088428, A088429. Sequence in context: A292746 A176506 A200596 * A100833 A097293 A296656 Adjacent sequences:  A088419 A088420 A088421 * A088423 A088424 A088425 KEYWORD easy,nonn AUTHOR Zak Seidov, Sep 29 2003 STATUS approved

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Last modified May 12 13:46 EDT 2021. Contains 343823 sequences. (Running on oeis4.)