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A088424 Number of primes in arithmetic progression starting with 13 and with d=2n. 9

%I

%S 1,2,2,1,2,1,1,2,2,1,1,3,1,2,4,1,2,1,1,2,1,1,2,4,1,1,2,1,2,2,1,1,2,1,

%T 2,1,1,2,1,1,1,3,1,2,6,1,2,2,1,2,1,1,1,1,1,1,3,1,2,1,1,2,2,1,1,1,1,2,

%U 2,1,1,2,1,1,5,1,2,1,1,2,1,1,2,3,1,1,1,1,2,3,1,2,2,1,1,1,1,1,4,1

%N Number of primes in arithmetic progression starting with 13 and with d=2n.

%C Arithmetic progression is stopped when next term is not prime. E.g. for n=15, a=4, that is 13,43,73,103 are prime, while next term, 133, is not prime.

%t bb={}; Do[s=1; Do[If[PrimeQ[13+k*d], s=s+1, bb={bb, s}; Break[]], {k, 10}], {d, 2, 200, 2}]; Flatten[bb]

%Y Cf. A088420, A088421, A088422, A088423, A088425, A088426, A088427, A088428, A088429.

%K easy,nonn

%O 1,2

%A _Zak Seidov_, Sep 29 2003

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Last modified June 19 17:53 EDT 2021. Contains 345144 sequences. (Running on oeis4.)