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 A070303 #18 Sep 11 2019 06:59:36
%S A070303 3,7,11,13,19,23,29,31,41,43,47,53,59,61,67,71,73,79,83,89,97,103,107,
%T A070303 109,113,127,131,137,139,149,151,157,163,167,173,179,181,191,193,199,
%U A070303 211,223,227,229,233,239,241,251,263,269,271,277,281,283,293,307,311
%N A070303 Primes p such that the equation p^2*x^2==0 (mod p^2+x^2) has no solution.
%H A070303 Amiram Eldar, <a href="/A070303/b070303.txt">Table of n, a(n) for n = 1..10000</a>
%F A070303 Primes not in A002496 (i.e., not of the form k^2+1).
%F A070303 a(n) ~ n log n. - _Charles R Greathouse IV_, Sep 30 2012
%t A070303 Select[Range[320], PrimeQ[#] && !IntegerQ @ Sqrt[# - 1] &] (* _Amiram Eldar_, Sep 11 2019 *)
%o A070303 (PARI) for(n=1,350,if(0==sum(i=1,n^2,if((n^2*i^2)%(n^2+i^2),1-isprime(n),1)),print1(n,",")))
%o A070303 (PARI) is(n)=isprime(n) && !issquare(n-1) \\ _Charles R Greathouse IV_, Sep 30 2012
%o A070303 (PARI) print1(3); forstep(k=2, 9, 2, forprime(p=k^2+3, (k+2)^2, print1(", "p))) \\ _Charles R Greathouse IV_, Sep 30 2012
%K A070303 easy,nonn
%O A070303 1,1
%A A070303 _Benoit Cloitre_, May 10 2002