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 A076883 #12 Nov 21 2013 12:47:54 %S A076883 1,2,5,12,30,75,187,467,1167,2917,7292,18230,45575,113937,284842, %T A076883 712105,1780262,4450655,11126637,27816592,69541480,173853700, %U A076883 434634250,1086585625,2716464062,6791160155,16977900387,42444750967,106111877417 %N A076883 Let u(0)=1, u(n) = 5/2 * floor(u(n-1)); then a(n) = (2/5)*u(n). %C A076883 May be equivalently defined by (1) a(n) = floor(u(n-1)) or (2) a(1) = 1, a(n) = floor(5/2 * a(n - 1)). - _Joel B. Lewis_, Jul 18 2008 %F A076883 a(n)=ceiling(c*(5/2)^n) with c=0.76461665854988933665808275090184088890217299... %t A076883 NestList[Floor[5/2 #]&,1,30] (* _Harvey P. Dale_, Apr 18 2012 *) %K A076883 nonn %O A076883 1,2 %A A076883 _Benoit Cloitre_, Nov 25 2002