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 A336238 #11 Jul 13 2020 21:35:26 %S A336238 3,5,8,2,7,13,20,5,14,7,18,3,16,8,23,39,56,28,47,67,88,4,27,9,34,17, %T A336238 44,11,40,4,35,67,100,50,10,5,42,21,7,47,88,44,87,131,176,88,135,45, %U A336238 94,47,98,49,102,17,72,9,3,61,120,2,63,125,188,47,112,56,123,191 %N A336238 a(1) = 3; if n>1, and gcd(a(n-1), n) > 1 then a(n) = a(n-1)/gcd(a(n-1), n), otherwise a(n) = a(n-1) + n. %H A336238 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,2,0,-1). %o A336238 (PARI) a(n) = if (n==1, 3, my(prec=a(n-1)); if (gcd(prec, n) > 1, prec/gcd(prec,n), n+prec)); \\ _Michel Marcus_, Jul 13 2020 %Y A336238 Cf. A093178. %K A336238 nonn,easy %O A336238 1,1 %A A336238 _Todor Szimeonov_, Jul 13 2020