A047982 a(n) = A047980(2n+1).
1, 24, 38, 184, 368, 668, 634, 512, 1028, 1468, 3382, 4106, 10012, 7628, 11282, 38032, 53630, 37274, 63334, 34108, 102296, 119074, 109474, 117206, 60664, 410942, 204614, 127942, 125618, 595358, 517882, 304702, 352022, 1549498, 651034, 506732, 5573116, 1379216, 1763144
Offset: 0
Keywords
Examples
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).
Links
Formula
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.
Extensions
More terms from Michel Marcus, Sep 01 2019