decompwlj 3D

The composite numbers: numbers n of the form x*y for x > 1 and y > 1

A002808 on the OEIS · family complement · also known as Composite numbers

Weight–level plate of The composite numbers: numbers n of the form x*y for x > 1 and y > 1
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 viewerA002808 on the OEIS
Terms100,000 (n = 1 … 100,000)
Decomposable (a > 2d)99,999
Level class, k > L10,575 · 10.58 %
Weight class, k ≤ L89,424 · 89.42 %
Ties, k = L66
On the level line L = 19,164
Forced level, l ≤ d²1
Range of a(n)4 … 110,487
Range of the jump d1 … 2
Largest weight k, level L110,479, 55,243

Composites: gaps of 1, and 2 across each prime. The naturals' plane, thinned: 10.58 % level against 9.59 %.

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.