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 A380414 #11 Jan 25 2025 12:50:05
%S A380414 1,2,2,4,4,4,4,4,4,4,4,4,6,8,6,4,8,8,4,8,4,4,4,4,8,4,4,6,4,4,4,4,4,4,
%T A380414 4,4,6,4,4,4,4,4,8,4,4,4,6,4,8,8,4,4,8,4,8,8,4,4,8,4,4,4,4,4,4,8,6,4,
%U A380414 8,4,4,8,4,8,8,4,4,8,4,4,6,4,4,8,4,4,4,4,4,8
%N A380414 a(n) = phi(2 + phi(3 + phi(4 + ... + phi(A246655(n))))), where phi is Euler's totient function (A000010).
%C A380414 Inspired by A380340, A380341 and A380342.
%C A380414 Conjecture 1: a(n) can be only 1, 2, 4, 6 or 8.
%C A380414 Conjecture 2: for n >= 1110, a(n) = 4.
%H A380414 Paolo Xausa, <a href="/A380414/b380414.txt">Table of n, a(n) for n = 1..10000</a>
%t A380414 With[{pp = Select[Range[1000], PrimePowerQ]}, Table[Fold[EulerPhi[#2 + #] &, 0, pp[[n ;; 1 ;; -1]]], {n, Length[pp]}]]
%Y A380414 Cf. A000010, A246655, A380340, A380341, A380342, A380354, A380415.
%K A380414 nonn
%O A380414 1,2
%A A380414 _Paolo Xausa_, Jan 24 2025