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 A057686 #15 Dec 12 2023 15:55:08 %S A057686 23,530,265,53,1220,610,305,61,1404,702,351,117,39,13,1,24,12,6,3,1, %T A057686 24,12,6,3,1,24,12,6,3,1,24,12,6,3,1,24,12,6,3,1,24,12,6,3,1,24,12,6, %U A057686 3,1,24,12,6,3,1,24,12,6,3,1,24,12,6,3,1,24,12,6,3,1 %N A057686 Trajectory of 23 under the `23x+1' map. %C A057686 See A057684 for definition. %H A057686 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,1). %t A057686 Px1[p_,n_]:=Catch[For[i=1,i<PrimePi[p],i++,If[Divisible[n,Prime[i]],Throw[n/Prime[i]]]];p*n+1]; %t A057686 NestList[Px1[23,#]&,23,100] (* _Paolo Xausa_, Dec 10 2023 *) %Y A057686 Cf. A057446, A057216, A057522, A057534, A057614. %Y A057686 See also A033478, A057688, A057684, A057685, A057686, A057687, A057689, A057690, A057691. %K A057686 nonn,easy %O A057686 0,1 %A A057686 _N. J. A. Sloane_, Oct 20 2000