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 A261768 #22 Feb 16 2025 08:33:27
%S A261768 0,-1,-1,0,399,28,162287,61440,9546255,1038576,74062575399,16756480,
%T A261768 83695120256591,78356634560,35181809198207,281470681743360,
%U A261768 246486713303685957375,101559922656192,604107995057426434824791,1152921479006846976
%N A261768 a(n) = phi(n)^n - n^phi(n), where phi(n) is Euler's totient function.
%C A261768 a(n) < n^n/e. If n is prime, a(n)/n^n = (1-1/n)^n - 1/n -> 1/e as n -> infinity. - _Robert Israel_, Sep 18 2015
%H A261768 Robert Israel, <a href="/A261768/b261768.txt">Table of n, a(n) for n = 1..388</a>
%H A261768 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/TotientFunction.html">Totient Function</a>
%F A261768 a(n) = A000010(n)^n - n^A000010(n) = A000010(n)^n - A062981(n).
%p A261768 seq(numtheory:-phi(n)^n - n^numtheory:-phi(n),n=1..30); # _Robert Israel_, Sep 18 2015
%t A261768 Table[EulerPhi[n]^n - n^EulerPhi[n], {n, 1, 20}]
%o A261768 (PARI) a(n) = eulerphi(n)^n - n^eulerphi(n) \\ _Anders Hellström_, Aug 31 2015
%o A261768 (Magma) [EulerPhi(n)^n-n^EulerPhi(n): n in [1..20]]; // _Vincenzo Librandi_, Sep 01 2015
%Y A261768 Cf. A000010, A062981.
%K A261768 sign
%O A261768 1,5
%A A261768 _Ilya Gutkovskiy_, Aug 31 2015