decompwlj 3D

Primes of form 10n+7

A030432 on the OEIS · family primes · also known as Primes ending in 7

Weight–level plate of Primes of form 10n+7
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 viewerA030432 on the OEIS
Terms100,000 (n = 1 … 100,000)
Decomposable (a > 2d)99,998
Level class, k > L37,301 · 37.30 %
Weight class, k ≤ L62,697 · 62.70 %
Ties, k = L0
On the level line L = 19,944
Forced level, l ≤ d²64
Range of a(n)7 … 5,798,447
Range of the jump d10 … 500
Largest weight k, level L5,798,197, 527,037

Primes ending in 7. Every gap is a multiple of 10, so l ends in 7; no square ends in 7, so there are no ties, by proof. The level share is 37.30 %.

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.