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 A272040 #48 Oct 22 2023 11:32:49
%S A272040 1,1,4,4,28,24,156,128,784,1120,5740,2880,33460,37128,150080,147456,
%T A272040 1128256,931392,6446016,4677120,28514304,44450560,224075664,106168320,
%U A272040 1265644800,1560708240,5970392064,5588803584,44560482148,33497856000,255263424000,196368924672,1210784762880
%N A272040 a(n) = A000010(A000129(n)).
%H A272040 Amiram Eldar, <a href="/A272040/b272040.txt">Table of n, a(n) for n = 1..630</a>
%e A272040 a(3) = 4 because a(3) = A000010(A000129(3)) = A000010(5) = 4.
%t A272040 EulerPhi[LinearRecurrence[{2, 1}, {1, 2}, 33]] (* _Amiram Eldar_, Oct 21 2023 *)
%o A272040 (PARI) a000129(n) = ([2,1;1,0]^n)[2,1];
%o A272040 a(n) = eulerphi(a000129(n));
%Y A272040 Cf. A000010, A000129, A000203, A065449, A363829, A363831, A363833, A364818.
%K A272040 nonn
%O A272040 1,3
%A A272040 _Altug Alkan_, May 06 2016