decompwlj 3D

Natural position of n in the string 12345678910111213...

A117804 on the OEIS · family digit rule · also known as Natural position of n in the string 12345678910111213

Weight–level plate of Natural position of n in the string 12345678910111213...
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 viewerA117804 on the OEIS
Terms100,000 (n = 1 … 100,000)
Decomposable (a > 2d)99,998
Level class, k > L10,703 · 10.70 %
Weight class, k ≤ L89,295 · 89.30 %
Ties, k = L12
On the level line L = 1188
Forced level, l ≤ d²0
Range of a(n)1 … 488,890
Range of the jump d1 … 6
Largest weight k, level L97,771, 81,480

6 different gaps occur, from 1 to 6; the level share is 10.70 %; L = 5 holds 79 % 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.