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 A332778 #4 Feb 23 2020 16:28:11
%S A332778 1,1,2,3,4,8,6,15,14,24,10,96,12,48,56,255,16,344,18,656,108,120,22,
%T A332778 9840,84,168,434,2448,28,4608,30,65535,260,288,264,137376,36,360,360,
%U A332778 432512,40,16776,42,14720,7208,528,46,96974880,258,9464,608,28656,52,425864,600
%N A332778 a(1) = 1; a(n) = Sum_{d|n, d < n} phi(n/d) * a(d)^2.
%F A332778 a(1) = 1; a(n) = Sum_{k=1..n-1} a(gcd(n, k))^2.
%t A332778 a[1] = 1; a[n_] := Sum[If[d < n, EulerPhi[n/d] a[d]^2, 0], {d, Divisors[n]}]; Table[a[n], {n, 1, 55}]
%t A332778 a[1] = 1; a[n_] := Sum[a[GCD[n, k]]^2, {k, 1, n - 1}]; Table[a[n], {n, 1, 55}]
%Y A332778 Cf. A000010, A006874, A007018, A023900, A069097, A082588.
%K A332778 nonn
%O A332778 1,3
%A A332778 _Ilya Gutkovskiy_, Feb 23 2020