A047982 - 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