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 A364212 #8 Jul 14 2023 09:04:02
%S A364212 1,4,17,88,481,2812,16808,102988,640545,4035604,25679569,164778696,
%T A364212 1064714401,6920652008,45214871857,296722645888,1954878268801,
%U A364212 12923917765876,85705978837393,569944761286648,3799631728468936,25388448380261788,169992219503608177,1140364472585830196
%N A364212 a(n) = (1/(6*n)) * Sum_{d|n} 7^(n/d-1) * phi(7*d).
%F A364212 G.f.: (-1/6) * Sum_{k>0} phi(7*k) * log(1-7*x^k)/(7*k).
%t A364212 a[n_] := DivisorSum[n, 7^(n/#-1)*EulerPhi[7*#]/(6*n) &]; Array[a, 25] (* _Amiram Eldar_, Jul 14 2023 *)
%o A364212 (PARI) a(n) = sumdiv(n, d, 7^(n/d-1)*eulerphi(7*d))/(6*n);
%Y A364212 Cf. A000010, A359099, A359102.
%Y A364212 Cf. A000013, A364210, A364211.
%K A364212 nonn
%O A364212 1,2
%A A364212 _Seiichi Manyama_, Jul 13 2023