cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A144840 Numbers k such that the three numbers k-1, k+3 and k+5 are all prime.

This page as a plain text file.
%I A144840 #10 Feb 16 2025 08:33:09
%S A144840 8,14,38,68,98,104,194,224,278,308,458,614,824,854,878,1088,1298,1424,
%T A144840 1448,1484,1664,1694,1784,1868,1874,1994,2084,2138,2378,2684,2708,
%U A144840 2798,3164,3254,3458,3464,3848,4154,4514,4784,5228,5414,5438,5648,5654,5738
%N A144840 Numbers k such that the three numbers k-1, k+3 and k+5 are all prime.
%H A144840 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PrimeTriplet.html">Prime Triplet</a>.
%F A144840 a(n) = A022005(n) + 1. - _R. J. Mathar_, Sep 24 2008
%o A144840 (Python)
%o A144840 from sympy import isprime
%o A144840 def ok(n): return n > 4 and isprime(n-1) and isprime(n+3) and isprime(n+5)
%o A144840 print(list(filter(ok, range(5739)))) # _Michael S. Branicky_, Aug 14 2021
%Y A144840 Cf. A022005, A086801, A144834.
%Y A144840 Cf. A098413, A144842.
%K A144840 easy,nonn
%O A144840 1,1
%A A144840 _Giovanni Teofilatto_, Sep 23 2008
%E A144840 Definition edited and extended by _R. J. Mathar_, Sep 24 2008