A088422 Number of primes in arithmetic progression starting with 7 and with d=2n.

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

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

Table of n, a(n) for n=1..105.

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