decompwlj 3D

Composite numbers that are not the sum of 2 primes

A025583 on the OEIS · family multiplicative

Weight–level plate of Composite numbers that are not the sum of 2 primes
Click the plate to explore it in 3-D. Weight k across, level L up, both on log scales: blue in the weight class (k ≤ L), orange in the level class (k > L). The dashed diagonal is k = L.
Open in the 3-D viewerA025583 on the OEIS
Terms100,000 (n = 1 … 100,000)
Decomposable (a > 2d)100,000
Level class, k > L5,404 · 5.40 %
Weight class, k ≤ L94,596 · 94.60 %
Ties, k = L84
On the level line L = 13,092
Forced level, l ≤ d²8
Range of a(n)27 … 297,197
Range of the jump d2 … 22
Largest weight k, level L297,161, 99,065

9 different gaps occur, from 2 to 22; the level share is 5.40 %; L = 1 holds 57 % 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.