decompwlj 3D

Numbers with a single 4 in their base 5 expansion

A023738 on the OEIS · family digit rule

Weight–level plate of Numbers with a single 4 in their base 5 expansion
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 viewerA023738 on the OEIS
Terms100,000 (n = 1 … 100,000)
Decomposable (a > 2d)99,998
Level class, k > L12,380 · 12.38 %
Weight class, k ≤ L87,618 · 87.62 %
Ties, k = L58
On the level line L = 18,637
Forced level, l ≤ d²42
Range of a(n)4 … 269,798
Range of the jump d1 … 3,911
Largest weight k, level L269,779, 134,898

13 different gaps occur, from 1 to 3,911; the level share is 12.38 %; L = 1 holds 70 % 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.