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 A016225 #23 Jul 08 2025 05:44:06
%S A016225 1,15,171,1795,18291,184275,1848211,18503955,185126931,1851618835,
%T A016225 18517586451,185181456915,1851836938771,18518458866195,
%U A016225 185184946575891,1851850897414675,18518514700769811,185185169914190355
%N A016225 Expansion of 1/((1-x)(1-4x)(1-10x)).
%H A016225 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (15,-54,40).
%F A016225 G.f.: 1/((1-x)*(1-4*x)*(1-10*x)).
%F A016225 a(n) = (50*10^n-24*4^n+1)/27. - _Paul Barry_, Feb 17 2003
%F A016225 a(n) = 14*a(n-1)-40*a(n-2)+1, n>=2. - _Vincenzo Librandi_, Feb 10 2011
%F A016225 a(n) = 15*a(n-1) - 54*a(n-2) + 40*a(n-3). - _Wesley Ivan Hurt_, May 25 2024
%p A016225 A016225 := proc(n) (50*10^n-24*4^n+1)/27 ; end proc:
%p A016225 seq(A016225(n),n=0..20) ; # _R. J. Mathar_, Mar 22 2011
%t A016225 Table[(50*10^n - 24*4^n + 1)/27, {n, 0, 20}] (* _Wesley Ivan Hurt_, May 25 2024 *)
%o A016225 (PARI) Vec(1/((1-x)*(1-4*x)*(1-10*x))+O(x^99)) \\ _Charles R Greathouse IV_, Sep 26 2012
%Y A016225 Cf. A080249, A080250, A002450.
%K A016225 nonn,easy
%O A016225 0,2
%A A016225 _N. J. A. Sloane_