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 A331407 #15 Feb 25 2020 18:32:51
%S A331407 1,2,8,32,128,864,3456,7776,31104,279936,497664,1990656,4478976,
%T A331407 17915904,62208000,97200000,559872000,874800000,1555200000,6220800000,
%U A331407 13996800000,55987200000
%N A331407 Numbers at which the sum of the iterated exponential totient function (A331273) attains a record.
%C A331407 Analogous to A181659 with the exponential totient function (A072911) instead of the Euler totient function phi (A000010).
%C A331407 The corresponding record values are 0, 1, 3, 5, 7, 11, 13, 19, 27, 37, 43, 51, 61, 75, 83, 101, 123, 147, 165, 195, 243, 293, ...
%t A331407 ephi[n_] := Times @@ EulerPhi[FactorInteger[n][[;; , 2]]]; s[n_] := Plus @@ FixedPointList[ephi, n] - n - 1; seq = {}; smax = -1; Do[s1 = s[n]; If[s1 > smax, smax = s1; AppendTo[seq, n]], {n, 1, 5000}]; seq
%Y A331407 Cf. A072911, A181659, A331273.
%K A331407 nonn,more
%O A331407 1,2
%A A331407 _Amiram Eldar_, Feb 25 2020