A144840 Numbers k such that the three numbers k-1, k+3 and k+5 are all prime.
8, 14, 38, 68, 98, 104, 194, 224, 278, 308, 458, 614, 824, 854, 878, 1088, 1298, 1424, 1448, 1484, 1664, 1694, 1784, 1868, 1874, 1994, 2084, 2138, 2378, 2684, 2708, 2798, 3164, 3254, 3458, 3464, 3848, 4154, 4514, 4784, 5228, 5414, 5438, 5648, 5654, 5738
Offset: 1
Links
- Eric Weisstein's World of Mathematics, Prime Triplet.
Programs
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Python
from sympy import isprime def ok(n): return n > 4 and isprime(n-1) and isprime(n+3) and isprime(n+5) print(list(filter(ok, range(5739)))) # Michael S. Branicky, Aug 14 2021
Formula
a(n) = A022005(n) + 1. - R. J. Mathar, Sep 24 2008
Extensions
Definition edited and extended by R. J. Mathar, Sep 24 2008