Primes congruent to 4 mod 21

Open in the 3-D viewerA141889 on the OEIS
| Terms | 100,000 (n = 1 … 100,000) |
|---|---|
| Decomposable (a > 2d) | 99,998 |
| Level class, k > L | 49,998 · 50.00 % |
| Weight class, k ≤ L | 50,000 · 50.00 % |
| Ties, k = L | 40 |
| On the level line L = 1 | 19,214 |
| Forced level, l ≤ d² | 242 |
| Range of a(n) | 67 … 18,833,077 |
| Range of the jump d | 42 … 1,764 |
| Largest weight k, level L | 18,832,909, 435,859 |
39 different gaps occur, from 42 to 1,764; the level share is 50.00 %; L = 1 holds 38 % of the level class.
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.