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 A342867 #11 May 06 2022 13:13:51 %S A342867 1,2,3,15,35,33,65,215,221,551,455,2001,3417,3621,11523,16705,16617, %T A342867 69845,107545,157285,324569,358883,1404949,1569295,3783970,3106285, %U A342867 7536065,12216295,10589487,24038979,57759065,51961945,177005465,131462695,741703701,1467144445 %N A342867 a(n) is the least number k such that the continued fraction for phi(k)/k contains exactly n elements. %C A342867 a(n) is the least number k such that A342866(k) = n. %C A342867 All the terms above 3 are composite numbers. %F A342867 a(2) = 2 since 2 is the least number k such that A342866(k) = 2. %t A342867 f[n_] := Length @ ContinuedFraction[EulerPhi[n]/n]; seq[max_] := Module[{s = Table[0, {max}], c = 0, n = 1, i}, While[c < max, i = f[n]; If[i <= max && s[[i]] == 0, c++; s[[i]] = n]; n++]; s]; seq[20] %o A342867 (PARI) a(n) = my(k=1); while (#contfrac(eulerphi(k)/k) != n, k++); k; \\ _Michel Marcus_, Mar 30 2021 %Y A342867 Cf. A000010, A007694, A076512, A109395, A342866. %Y A342867 Cf. A071865 (similar, with sigma(k)/k). %K A342867 nonn %O A342867 1,2 %A A342867 _Amiram Eldar_, Mar 27 2021