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 A339873 #6 Dec 28 2020 09:51:22 %S A339873 0,0,4,0,6,0,6,8,10,0,12,0,12,8,16,0,18,0,18,20,22,0,24,24,24,24,28,0, %T A339873 30,0,30,32,34,24,36,0,36,32,40,0,42,0,42,44,46,0,48,48,48,48,52,0,54, %U A339873 48,54,56,58,0,60,0,60,56,64,60,66,0,66,68,70,0,72,0,72,72,76,72,78,0,78,80,82,0,84,84,84,80 %N A339873 a(n) = 1 + n - A143771(n). %H A339873 Antti Karttunen, <a href="/A339873/b339873.txt">Table of n, a(n) for n = 2..65539</a> %o A339873 (PARI) %o A339873 A143771(n) = my(d = divisors(n)); gcd(vector(#d, k, d[k]+n/d[k])); \\ From A143771. %o A339873 A339873(n) = (1+n-A143771(n)); %Y A339873 Cf. A143771, A339914. %K A339873 nonn %O A339873 2,3 %A A339873 _Antti Karttunen_, Dec 25 2020