A067024 Smallest prime p such that p+2 has exactly n distinct prime factors.
2, 13, 103, 1153, 15013, 255253, 4849843, 111546433, 4360010653, 100280245063, 5245694198743, 152125131763603, 7149881192889433, 421842990380476663, 16294579238595022363, 1106494163767990292293, 74135108972455349583763, 4632891063696575353839163, 278970415063349480483707693, 24012274383139350058948392193
Offset: 1
Keywords
Examples
For n = 1,...,7 the factors of 2+a(n) are as follows: 2*2, 3*5, 3*5*7, 3*5*7*11, 3*5*7*11*13, 3*5*7*11*13*17, 3*5*7*11*13*17*19; i.e., a(n) = A002110(n+1)/2 which is prime for n = 2,...,7.
Links
- Sean A. Irvine, Table of n, a(n) for n = 1..58 (terms 1..38 from Michael S. Branicky)
- Michael S. Branicky, Python program
- Sean A. Irvine, Java program (github)
Programs
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Python
# see linked program
Extensions
a(8)-a(15) from Donovan Johnson, Jan 21 2009
a(16) and beyond from Michael S. Branicky, Feb 07 2023