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 A135056 #22 Feb 16 2025 08:33:07
%S A135056 0,1,2,3,4,10,20,39,76,149,294,578,1136,2233,4390,8631,16968,33358,
%T A135056 65580,128927,253464,498297,979626,1925894,3786208,7443489,14633514,
%U A135056 28768731,56557836,111189778,218593348,429743207,844852900
%N A135056 Pentanacci numbers: a(n) = a(n-1) + a(n-2) + a(n-3) + a(n-4) + a(n-5) if n>=5, and a(n) = n otherwise.
%H A135056 G. C. Greubel, <a href="/A135056/b135056.txt">Table of n, a(n) for n = 0..1000</a>
%H A135056 Piezas, Tito III and Weisstein, Eric W., <a href="https://mathworld.wolfram.com/PentanacciNumber.html">Pentanacci Number</a>.
%H A135056 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,1,1,1).
%F A135056 G.f.: x*(x-1)*(2*x^2+2*x+1)/(-1+x^5+x^4+x^3+x^2+x). - Maksym Voznyy (voznyy(AT)mail.ru), Aug 12 2009
%t A135056 a[n_] := a[n] = a[n - 1] + a[n - 2] + a[n - 3] + a[n - 4] + a[n - 5]; a[0] = 0; a[1] = 1; a[2] = 2; a[3] = 3; a[4] = 4; Table[a[n], {n, 0, 50}] (* _Artur Jasinski_, Nov 18 2007 *)
%t A135056 LinearRecurrence[{1,1,1,1,1},Range[0,4],40] (* _Harvey P. Dale_, Oct 18 2013 *)
%Y A135056 Cf. A001591, A135055.
%K A135056 nonn
%O A135056 0,3
%A A135056 _Artur Jasinski_, Nov 15 2007, Nov 18 2007