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 A200071 #21 Jun 30 2023 03:54:35
%S A200071 447,2042,4942,8673,17232,18321,38232,52953,54468,54974,55174,57229,
%T A200071 66567,71132,83071,101499,113667,121206,133047,173932,297907,325286,
%U A200071 430353,447131,656079,702969,842151,937313,1061846,1173886,1613346,1721094,1754679,1759310
%N A200071 Numbers n such that the sum of the prime distinct divisors of n^2+1 equals 2 times the difference between the largest and the smallest prime divisor.
%H A200071 Amiram Eldar, <a href="/A200071/b200071.txt">Table of n, a(n) for n = 1..500</a>
%e A200071 447 is a term because the distinct prime divisors of 447^2 + 1 are 2, 5, 13, 29, 53 and their sum, 2 + 5 + 13 + 29 + 53 = 102, equals 2*(53 - 2).
%t A200071 Select[Range[1800000],Plus@@(pl=First/@FactorInteger[#^2+1])/2==pl[[-1]]-pl[[1]]&]
%t A200071 spddQ[n_]:=Module[{fi=FactorInteger[n^2+1][[All,1]]},Total[fi] == 2*(Last[ fi]-First[fi])]; Select[Range[176*10^4],spddQ] (* _Harvey P. Dale_, Jan 12 2019 *)
%Y A200071 Cf. A200070.
%K A200071 nonn
%O A200071 1,1
%A A200071 _Michel Lagneau_, Nov 13 2011