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 A067920 #15 Feb 10 2025 14:09:47
%S A067920 2,2,2,4,11,14,57,100,1778,2355,7690,21334,89831,126718,365351,665175,
%T A067920 914152,1469797,3554254,25042522,190651419,580715831,1803513148,
%U A067920 3705699670,44927205487,232354919706,1600668490436,7538452976365,12294187702836,28817421277388
%N A067920 Engel expansion of sin(2).
%t A067920 EngelExp[A_, n_]:=Join[Array[1&, Floor[A]], First@Transpose@NestList[{Ceiling[1/Expand[ #[[1]]#[[2]]-1]], Expand[ #[[1]]#[[2]]-1]}&, {Ceiling[1/(A-Floor[A])], A-Floor[A]}, n-1]]; EngelExp[N[Sin[2], 7!], 30] (* _Georg Fischer_, Nov 20 2020 *)
%o A067920 (PARI) my(r=sin(2)); for(i=1, 20, my(s=r*ceil(1/r)-1); print1(ceil(1/r), ", "); r=s); /* _Benoit Cloitre_ [amended by _Georg Fischer_, Nov 20 2020] */
%Y A067920 See A006784 for explanation of Engel expansions.
%K A067920 easy,nonn
%O A067920 1,1
%A A067920 _Benoit Cloitre_, Mar 03 2002
%E A067920 a(1)=2 inserted and a(29),a(30) from _Georg Fischer_, Nov 20 2020