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 A196731 #25 Mar 25 2025 11:52:58
%S A196731 1,11,132,1584,19008,228096,2737152,32845824,394149888,4729798656,
%T A196731 56757583872,681091006464,8173092077568,98077104930816,
%U A196731 1176925259169792,14123103110037504,169477237320450048,2033726847845400576,24404722174144806912,292856666089737682944,3514279993076852195328
%N A196731 Expansion of g.f. (1-x)/(1-12*x).
%H A196731 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (12).
%F A196731 a(n) = Sum_{k=0..n} A193722(n,k)*9^(n-k).
%F A196731 a(n+1) = 12*a(n) for n > 0. - _M. F. Hasler_, Oct 05 2011
%F A196731 From _Elmo R. Oliveira_, Mar 18 2025: (Start)
%F A196731 a(n) = 11*12^(n-1) with a(0)=1.
%F A196731 E.g.f.: (11*exp(12*x) + 1)/12. (End)
%p A196731 a:= n-> ceil(11*12^(n-1)):
%p A196731 seq(a(n), n=0..20); # _Alois P. Heinz_, Mar 25 2025
%t A196731 Join[{1},NestList[12#&,11,20]] (* _Harvey P. Dale_, Sep 19 2018 *)
%o A196731 (PARI) a(n)=if(n,11*12^n--,1) \\ _Charles R Greathouse IV_, Oct 05 2011
%o A196731 (PARI) a(n)=(11+!n)*12^(n-1) \\ _M. F. Hasler_, Oct 05 2011
%Y A196731 Cf. A002001, A005054, A025192, A052934, A055272, A055274, A055276, A193722.
%K A196731 nonn,easy
%O A196731 0,2
%A A196731 _Philippe Deléham_, Oct 05 2011
%E A196731 More terms from _Elmo R. Oliveira_, Mar 25 2025