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 A080231 #3 Mar 31 2012 13:21:55 %S A080231 -1,-2,-3,-4,-9,-11,-17,-82,-86,-89,-259,-1031,-1493,-3088,-18107, %T A080231 -3128320,-4245574,-4430458,-6692218,-6908807,-20282631,-55597679, %U A080231 -73203786,-80410013,-92821351,-192936649,-5039379072,-30234138756,-55272287466,-202248991637 %N A080231 Engel expansion for (negative) constant defined in A078756. %F A080231 See A006784 for definition of Engel expansion %o A080231 (PARI) x=vector(31); a=vector(30); x[1]=-0.62923321313860758778445822033246963679442280615921 for (i=1,30,a[i]=ceil(1/x[i]); x[i+1]=x[i]*a[i]-1); x %Y A080231 Cf. A006784, A078756, A080320. %K A080231 sign %O A080231 1,2 %A A080231 _Jon Perry_, Feb 08 2003