decompwlj 3D

Numbers with no pair (d,e) of divisors such that d < e < 2*d

A174905 on the OEIS · family divisor functions

Weight–level plate of Numbers with no pair (d,e) of divisors such that d < e < 2*d
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 viewerA174905 on the OEIS
Terms100,000 (n = 1 … 100,000)
Decomposable (a > 2d)99,998
Level class, k > L8,561 · 8.56 %
Weight class, k ≤ L91,437 · 91.44 %
Ties, k = L84
On the level line L = 17,511
Forced level, l ≤ d²1
Range of a(n)1 … 186,185
Range of the jump d1 … 12
Largest weight k, level L186,157, 93,090

12 different gaps occur, from 1 to 12; the level share is 8.56 %; L = 1 holds 88 % 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.