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 A248530 #11 Sep 08 2022 08:46:10 %S A248530 6,80,154,290,364,376,524,586,660,734,894,1030,1104,1116,1190,1326, %T A248530 1400,1486,1634,1770,1856,1930,2004,2066,2226,2300,2510,2584,2596, %U A248530 2744,2806,2880,2966,3040,3114,3176,3250,3324,3484,3546,3620,3694,3706,3780,3854,3916 %N A248530 Numbers n such that the smallest prime divisor of n^2+1 is 37. %C A248530 Or numbers n such that the smallest prime divisor of n^2+1 is A002313(6). %C A248530 a(n)== 6 or 68 (mod 74). %H A248530 Amiram Eldar, <a href="/A248530/b248530.txt">Table of n, a(n) for n = 1..10000</a> %e A248530 80 is in the sequence because 80^2+1= 37*173. %t A248530 lst={};Do[If[FactorInteger[n^2+1][[1, 1]]==37, AppendTo[lst, n]], {n, 2, 4000}]; lst %t A248530 p = 37; ps = Select[Range[p - 1], Mod[#, 4] != 3 && PrimeQ[#] &]; Select[Range[4000], Divisible[(nn = #^2 + 1), p] && ! Or @@ Divisible[nn, ps] &] (* _Amiram Eldar_, Aug 16 2019 *) %o A248530 (Magma) [n: n in [2..4000] | PrimeDivisors(n^2+1)[1] eq 37]; // _Bruno Berselli_, Oct 08 2014 %Y A248530 Cf. A089120, A002313, A209874, A248527, A248528, A248529. %K A248530 nonn,easy %O A248530 1,1 %A A248530 _Michel Lagneau_, Oct 08 2014