Primes congruent to 17 mod 21

Open in the 3-D viewerA141896 on the OEIS
| Terms | 100,000 (n = 1 … 100,000) |
|---|---|
| Decomposable (a > 2d) | 99,997 |
| Level class, k > L | 49,968 · 49.97 % |
| Weight class, k ≤ L | 50,029 · 50.03 % |
| Ties, k = L | 0 |
| On the level line L = 1 | 19,357 |
| Forced level, l ≤ d² | 241 |
| Range of a(n) | 17 … 18,823,703 |
| Range of the jump d | 42 … 1,638 |
| Largest weight k, level L | 18,823,157, 436,145 |
39 different gaps occur, from 42 to 1,638; the level share is 49.97 %; L = 1 holds 39 % of the level class; there are no ties.
The decomposition
Every term of a strictly increasing sequence is written a(n) = k(n)·L(n) + d(n): the jump d = a(n+1) − a(n), the weight k the least divisor of a − d greater than d, the level L = (a − d)/k. A term decomposes when a > 2d; it is in the level class when k > L and in the weight class when k ≤ L. See decompwlj.com and arXiv:0711.0865, or how it works, with worked examples and a live one.