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 A133180 #10 Sep 23 2024 08:08:33
%S A133180 1,13,163,373,2191,3433,7411,10363,24583,31591,49981,61723,109513,
%T A133180 130351,180793,210901,324013,370273,477463,539041,759811,846613,
%U A133180 1042303,1151983,1533331,1679323,2002321,2180263,2785693,3013051,3509221
%N A133180 a(n) = (Sum_{k=1..A047380(n)} k^6) / (Sum_{k=1..A047380(n)} k^2).
%C A133180 A000540(n) is divisible by A000330(n) if and only if n is congruent to {1,2,4,5} mod 7 (see A047380).
%C A133180 This sequence is the union of A134158 and A134159 and A134160 and A134161.
%F A133180 a(n) = A000540(A047380(n)) / A000330(A047380(n)). - _Jason Yuen_, Sep 23 2024
%t A133180 a = {}; Do[j = Sum[k^6, {k, 1, n}]/Sum[k^2, {k, 1, n}]; If[IntegerQ[j], AppendTo[a, j]], {n, 1, 100}] ; a (*Artur Jasinski*)
%t A133180 Select[Table[Sum[k^6,{k,n}]/Sum[k^2,{k,n}],{n,100}],IntegerQ] (* _Harvey P. Dale_, Nov 26 2019 *)
%Y A133180 Cf. A000330, A000540, A047380, A119617, A134153, A134154, A134158, A134159, A134160, A134161.
%K A133180 nonn,easy
%O A133180 1,2
%A A133180 _Artur Jasinski_, Oct 10 2007
%E A133180 Offset corrected by _Jason Yuen_, Sep 23 2024