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.
%I A067268 #17 Sep 08 2022 08:45:05 %S A067268 2,4,12,15,16,18,22,28,34,35,38,39,44,45,46,48,50,51,52,58,62,65,68, %T A067268 69,76,80,82,85,86,88,92,95,96,100,104,105,106,108,118,132,136,138, %U A067268 141,144,145,152,158,159,164,166,171,174,175,178,188,194,196,201,202,205 %N A067268 Numbers k such that k and k^2+1 have the same number of distinct prime factors. %H A067268 Amiram Eldar, <a href="/A067268/b067268.txt">Table of n, a(n) for n = 1..10000</a> %F A067268 Numbers k such that omega(k) = omega(k^2+1). %e A067268 2 is a term since omega(2) = omega(2^2+1) = 1. %t A067268 Select[Range[250],PrimeNu[#]==PrimeNu[#^2+1]&] (* _Harvey P. Dale_, Feb 07 2019 *) %o A067268 (Magma) [k:k in [1.. 210 ]| #PrimeDivisors(k) eq #PrimeDivisors(k^2+1)]; // _Marius A. Burtea_, Feb 18 2020 %Y A067268 Cf. A001221, A002522, A128428, A272044. %K A067268 easy,nonn %O A067268 1,1 %A A067268 _Benoit Cloitre_, Feb 21 2002