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 A051172 #18 Feb 24 2025 10:56:23
%S A051172 0,1,4,12,30,66,132,245,429,715,1144,1768,2652,3876,5537,7752,10659,
%T A051172 14421,19228,25300,32890,42287,53820,67860,84825,105183,129456,158224,
%U A051172 192129,231880,278256,332112,394383,466089,548340
%N A051172 T(n,7), array T as in A051168; a count of Lyndon words; aperiodic necklaces with 7 black beads and n-7 white beads.
%H A051172 <a href="/index/Lu#Lyndon">Index entries for sequences related to Lyndon words</a>
%H A051172 <a href="/index/Rec#order_13">Index entries for linear recurrences with constant coefficients</a>, signature (6,-15,20,-15,6,-1,1,-6,15,-20,15,-6,1).
%F A051172 G.f.: -(x^7/7)*(1/(1- x^7)+1/(-1+x)^7). - _Herbert Kociemba_, Oct 16 2016
%t A051172 Drop[CoefficientList[Series[-(x^7/7)*(1/(1-x^7)+1/(-1+x)^7),{x,0,50}],x],7] (* _Harvey P. Dale_, Aug 04 2024 *)
%Y A051172 Cf. A000031, A001037, A051168. Same as A011797(n-1).
%K A051172 nonn
%O A051172 7,3
%A A051172 _Clark Kimberling_
%E A051172 a(20) corrected by _Herbert Kociemba_, Oct 16 2016