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 A083252 #19 Feb 03 2025 02:16:36
%S A083252 5,105,315,182835,960075,7838265,4291166265
%N A083252 Numbers k for which abs(A045763(k) - A073757(k)) = 5, i.e., signed difference of size of related and unrelated sets to k equals either 5 or -5.
%C A083252 a(7), if it exists, is > 10^9. - _Vaclav Kotesovec_, Sep 06 2019
%e A083252 For k = 960075: d = 36 divisors, r = 480000 coprimes, u = 480040 unrelated; k - u = r + d - 1 = 480035 related numbers to k; thus abs(480040 - 480035) = 5.
%t A083252 Do[r=EulerPhi[n]; d=DivisorSigma[0, n]; u=n-r-d+1; df=2*u-n; If[Equal[Abs[df], 5], Print[n(*, {d, r, u}*)]], {n, 1, 3000}]
%o A083252 (PARI) isok(n) = abs(n-2*eulerphi(n)-2*numdiv(n)+2) == 5; \\ _Michel Marcus_, Jul 29 2017
%Y A083252 Cf. A000005, A000010, A045763, A073757, A083243-A083249, A083250, A083251.
%K A083252 nonn,more
%O A083252 1,1
%A A083252 _Labos Elemer_, May 07 2003
%E A083252 a(6) from _Michel Marcus_, Jul 29 2017
%E A083252 a(7) from _Amiram Eldar_, Feb 02 2025