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 A038225 #24 Mar 12 2024 08:01:15 %S A038225 1,4,30,246,2037,16886,139997,1160693,9623140,79784098,661478734, %T A038225 5484227157,45468956106,376976720745,3125460977225,25912757426660, %U A038225 214839027697334,1781200165693270,14767680082482085,122436758775876478 %N A038225 Top line of 4-wave sequence A038197, also bisection of A006357. %H A038225 Floor van Lamoen, <a href="https://web.archive.org/web/20171113001512/http://home.wxs.nl/~lamoen/wiskunde/wave.htm">Wave sequences</a> %H A038225 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (10,-15,7,-1). %F A038225 Let v(4) = (1, 1, 1, 1), let M(4) be the 4 X 4 matrix m(i, j) = min(i, j); then a(n) = min(v(4)*M(4)^n). - _Benoit Cloitre_, Oct 03 2002 %F A038225 G.f.: ( 1-6*x+5*x^2-x^3 ) / ( (x-1)*(x^3-6*x^2+9*x-1) ). - _Wouter Meeussen_, Mar 19 2005 %o A038225 (PARI) k=4; M(k)=matrix(k,k,i,j,min(i,j)); v(k)=vector(k,i,1); a(n)=vecmin(v(k)*M(k)^n) %Y A038225 Cf. A006357, A038197. %K A038225 nonn,easy %O A038225 0,2 %A A038225 _Floor van Lamoen_