decompwlj 3D

Primes p such that 2*p-1 and 2*p+1 are semiprimes

A086006 on the OEIS · family primes

Weight–level plate of Primes p such that 2*p-1 and 2*p+1 are semiprimes
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 viewerA086006 on the OEIS
Terms100,000 (n = 1 … 100,000)
Decomposable (a > 2d)99,999
Level class, k > L49,786 · 49.79 %
Weight class, k ≤ L50,213 · 50.21 %
Ties, k = L2
On the level line L = 18,911
Forced level, l ≤ d²614
Range of a(n)17 … 48,007,961
Range of the jump d2 … 6,702
Largest weight k, level L48,003,013, 15,903,719

1,510 different gaps occur, from 2 to 6,702; the level share is 49.79 %.

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.