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 A106474 #11 Apr 26 2023 05:37:28
%S A106474 1,3,7,8,13,19,19,20,33,35,31,48,37,51,75,48,49,87,55,88,109,83,67,
%T A106474 116,105,99,135,128,85,195,91,112,177,131,199,216,109,147,211,212,121,
%U A106474 283,127,208,333,179,139,272,217,275,279,248,157,351,323,308,313,227,175
%N A106474 a(n) = A006579(4n+4)/4.
%H A106474 Amiram Eldar, <a href="/A106474/b106474.txt">Table of n, a(n) for n = 0..10000</a>
%F A106474 a(n) = Sum_{k=0..4n+2} gcd(4n-k+3, k+1)/4.
%t A106474 Table[Sum[GCD[4n-k+3,k+1]/4,{k,0,4n+2}],{n,0,60}] (* _Harvey P. Dale_, May 19 2019 *)
%t A106474 f[p_, e_] := (e*(p - 1)/p + 1)*p^e; a[n_] := (Times @@ f @@@ FactorInteger[4*n+4]) / 4 - n - 1; Array[a, 100, 0] (* _Amiram Eldar_, Apr 26 2023 *)
%Y A106474 Cf. A006579.
%K A106474 easy,nonn
%O A106474 0,2
%A A106474 _Paul Barry_, May 03 2005