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A144840
Numbers k such that the three numbers k-1, k+3 and k+5 are all prime.
1
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
1,1
LINKS
Eric Weisstein's World of Mathematics, Prime Triplet.
FORMULA
a(n) = A022005(n) + 1. - R. J. Mathar, Sep 24 2008
PROG
(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
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Giovanni Teofilatto, Sep 23 2008
EXTENSIONS
Definition edited and extended by R. J. Mathar, Sep 24 2008
STATUS
approved