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 A199924 #19 Feb 24 2020 08:12:52 %S A199924 948,1560,1772,2153,2697,8487,11293,12553,13236,18065,32247,36984, %T A199924 40452,43999,55945,94536,100512,107607,127224,134223,214641,218783, %U A199924 366937,425808,429855,595471,620865,645327,757382,850416,875784,1241106,1330849,1363977,1387689 %N A199924 Numbers k such that the sum of the largest and the smallest prime divisor of k^2 + 1 equals the sum of the other distinct prime divisors. %C A199924 Generalization of A192770 and A192771. %H A199924 Amiram Eldar, <a href="/A199924/b199924.txt">Table of n, a(n) for n = 1..200</a> %e A199924 2697 is in the sequence because 2697^2 + 1 = 7273810 has five distinct divisors 2, 5, 41, 113, 157 and 157 + 2 = 5 + 41 + 113 = 159. %t A199924 Select[Range[1400000],Plus@@((pl=First/@FactorInteger[#^2+1])/2)==pl[[1]]+pl[[-1]]&](* program of _Ray Chandler_ adapted for this sequence - see A199745 *) %Y A199924 Cf. A180278, A192771, A192770. %K A199924 nonn %O A199924 1,1 %A A199924 _Michel Lagneau_, Nov 12 2011