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 A155631 #19 Jul 22 2025 06:19:14
%S A155631 1,7,85,937,9745,98977,995905,9983617,99934465,999737857,9998951425,
%T A155631 99995805697,999983222785,9999932891137,99999731564545,
%U A155631 999998926258177,9999995705032705,99999982820130817,999999931280523265
%N A155631 10^n-4^n+1^n.
%H A155631 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (15,-54,40).
%F A155631 G.f.: 1/(1-10*x)-1/(1-4*x)+1/(1-x). E.g.f.: e^(10*x)-e^(4*x)+e^x.
%F A155631 a(n)=14*a(n-1)-40*a(n-2)+27 with a(0)=1, a(1)=7 - _Vincenzo Librandi_, Jul 21 2010
%t A155631 LinearRecurrence[{15,-54,40},{1,7,85},30] (* _Harvey P. Dale_, Aug 30 2017 *)
%o A155631 (PARI) a(n)=10^n-4^n+1 \\ _Charles R Greathouse IV_, Sep 24 2015
%Y A155631 Cf. A155596, A155597, A155598, A155599, A155600, A155601, A155622, A155623, A155624, A155625, A155626, A155627, A155628, A155629, A155630.
%K A155631 nonn,easy
%O A155631 0,2
%A A155631 _Mohammad K. Azarian_, Jan 30 2009