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 A082129 #9 Dec 27 2023 00:24:42 %S A082129 3,1,5,4,6,9,17,22,33,53,76,114,171,260,390,585,874,1311,1970 %N A082129 Rounded base-2 logarithm of A082128(n+4). %o A082129 (PARI) p=21*4*5*13; for(n=1, 50, v=divisors(p); r=sqrt(p); t=0; for(k=1, matsize(v)[2], if(v[k]>=r, t=k; break)); if(v[t]^2==p, u=t, u=t-1); if(v[t]-v[u]<2, u=u-1; t=t+1); print1(round(log(v[t]-v[u])/log(2))", "); p=p*(v[t]-v[u])) %Y A082129 Cf. A082127, A082128. %K A082129 nonn,hard %O A082129 0,1 %A A082129 _Ralf Stephan_, Apr 04 2003