Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #16 Sep 01 2019 07:09:25
%S 1,24,38,184,368,668,634,512,1028,1468,3382,4106,10012,7628,11282,
%T 38032,53630,37274,63334,34108,102296,119074,109474,117206,60664,
%U 410942,204614,127942,125618,595358,517882,304702,352022,1549498,651034,506732,5573116,1379216,1763144
%N a(n) = A047980(2n+1).
%H Milan Janjic, <a href="http://www.pmfbl.org/janjic/">Enumerative Formulas for Some Functions on Finite Sets</a>
%H <a href="/index/Pri#primes_AP">Index entries for sequences related to primes in arithmetic progressions</a>
%F a(n) = min {d}: A034693(a(n)) is an odd number k such that in a(n)*k+1 progression the first prime occurs at k=2n+1 position.
%e a(2)=38 because A034693(38) = 2*2+1 = 5 is the first 5; 5*38+1 = 191 is the first prime. The successive progressions in which the first prime appears at position 5 are as follows: 38k+1, 62k+1, 164k+1. 2nd example: a(20)=102296 because. The first 41 appears in A034693 at this index. Also 102296*(2*20+1)+1 = 102296*41+1 = 4194137 is the first prime in {102296k+1}. The next progression with this position of prime emergence is 109946k+1 (the corresponding prime is 4507787).
%Y Cf. A047980, A047981, A034782, A034783, A034784.
%K nonn
%O 0,2
%A _Labos Elemer_
%E More terms from _Michel Marcus_, Sep 01 2019