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 A156641 #30 Sep 04 2024 18:55:18 %S A156641 13,1313,131313,13131313,1313131313,131313131313,13131313131313, %T A156641 1313131313131313,131313131313131313,13131313131313131313, %U A156641 1313131313131313131313,131313131313131313131313 %N A156641 a(n) = 13*(100^(n+1) - 1)/99. %H A156641 Vincenzo Librandi, <a href="/A156641/b156641.txt">Table of n, a(n) for n = 0..100</a> %H A156641 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (101,-100). %F A156641 G.f.: 13*x / ( (1-100*x)*(1-x) ). %F A156641 a(n) = 13*A094028(n-1). %F A156641 E.g.f.: (13/99)*(-exp(x) + 100*exp(100*x)). - _G. C. Greubel_, Feb 28 2021 %e A156641 For n=0, a(0)=13; n=1, a(1)=1313; n=2, a(2)=131313; n=3, a(3)=13131313. %p A156641 A156641:= n-> (13/99)*(10^(2*n+2) -1); seq(A156641(n), n=0..15); # _G. C. Greubel_, Feb 28 2021 %t A156641 Table[FromDigits[PadLeft[{1,3},2n,{1,3}]],{n,15}] (* _Harvey P. Dale_, Jul 23 2011 *) %o A156641 (Magma) [13*(100^(n+1)-1)/99: n in [0..15]]; %o A156641 (Sage) [(13/99)*(10^(2*n+2) -1) for n in (0..15)] # _G. C. Greubel_, Feb 28 2021 %o A156641 (PARI) a(n) = 100^(n+1)\99*13; \\ _Kevin Ryde_, Mar 05 2022 %Y A156641 Cf. A094028, A037582. %K A156641 nonn,easy %O A156641 0,1 %A A156641 _Vincenzo Librandi_, Feb 15 2009 %E A156641 Offset changed from 1 to 0