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 A063439 #30 Dec 10 2024 09:58:15
%S A063439 1,1,4,4,256,4,46656,256,46656,256,10000000000,256,8916100448256,
%T A063439 46656,16777216,16777216,18446744073709551616,46656,
%U A063439 39346408075296537575424,16777216,8916100448256,10000000000,341427877364219557396646723584,16777216,104857600000000000000000000
%N A063439 a(n) = phi(n)^phi(n).
%C A063439 Number of endofunctions over RRS[n]. Used in proof of Dirichlet theorem to derive characters: a(n) = A000312(A000010(n)). - _Labos Elemer_, May 27 2002
%C A063439 Sum_{n>=1} 1/phi(n)^phi(n) ~ 2.765711032... and so apparently equals Sum_{n>=1} A014197(n)/n^n where A014197(n) is the number of numbers m such that phi(m) = n. Is this a known result? - _Gerald McGarvey_, May 16 2004
%C A063439 The equality above is true and it is not unique for phi: for each value k = phi(n) the summand 1/phi(n)^phi(n) appears A014197(k) times, so Sum_{n>=1} 1/phi(n)^phi(n) = Sum_{k>=1} A014197(k) * (1/k^k). - _Amiram Eldar_, Dec 10 2024
%H A063439 Harry J. Smith, <a href="/A063439/b063439.txt">Table of n, a(n) for n = 1..200</a>
%F A063439 n log n / (log log n) << log a(n) < n log n. - _Charles R Greathouse IV_, Jan 19 2012
%t A063439 Table[EulerPhi[n]^EulerPhi[n], {n, 30}] (* _Vincenzo Librandi_, Dec 29 2019 *)
%o A063439 (PARI) { for (n=1, 200, p=eulerphi(n); write("b063439.txt", n, " ", p^p) ) } \\ _Harry J. Smith_, Aug 21 2009
%o A063439 (Magma) [EulerPhi(n)^EulerPhi(n): n in [1..30]]; // _Vincenzo Librandi_, Dec 29 2019
%Y A063439 Cf. A000010, A000312, A014197.
%K A063439 nonn
%O A063439 1,3
%A A063439 _Reinhard Zumkeller_, Jul 24 2001