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 A225856 #10 Feb 23 2021 05:22:51 %S A225856 2,3,5,11,13,17,19,23,29,31,37,47,53,59,61,67,71,73,79,83,89,97,101, %T A225856 103,109,113,127,131,137,139,149,151,163,167,173,179,181,191,197,199, %U A225856 211,223,227,229,233,241,263,269,271,277,281,283,311,313,317,331,337 %N A225856 Primes p such that p^2 + 1 is squarefree. %C A225856 Primes of the sequence A224718 generating squarefree. %H A225856 Amiram Eldar, <a href="/A225856/b225856.txt">Table of n, a(n) for n = 1..10000</a> %e A225856 23 is a term since 23^2+1 = 530 = 2*5*53, is squarefree. %e A225856 43 is not a term since 43^2+1 = 1850 = 2*5^2*7, is not squarefree. %t A225856 Select[Prime[Range[100]], SquareFreeQ[#^2+1]&] %Y A225856 Intersection of A000040 and A049533. %Y A225856 Cf. A224718. %K A225856 nonn %O A225856 1,1 %A A225856 _Rafael Parra Machio_, May 18 2013