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 A086858 #15 Nov 29 2024 09:58:39 %S A086858 1,1,1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,3,3,3,3,3,3,3,3, %T A086858 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3, %U A086858 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3 %N A086858 Let f(n) be the inverse of the function g(x) = x^x. Then a(n) = floor(f(n)). %C A086858 a(n) is the value of x that solves the equation x^x = n, truncated to an integer. %F A086858 a(n) = floor(g^-1(n)) where g(x) = x^x. %F A086858 a(n) ~ log n/log log n. - _Charles R Greathouse IV_, Nov 29 2024 %e A086858 a(32)=3 because the solution to the equation x^x = 32 is x = 3.080448349..., and floor(3.080448349...) = 3. %t A086858 f[n_] := Floor[ N[ Log[n]/ProductLog[Log[ n]]]]; Join[{1}, Table[ f[n], {n, 2, 105}]] (* _Robert G. Wilson v_, Oct 21 2005 *) %o A086858 (PARI) a(n)=exp(lambertw(log(x)))\1 \\ _Charles R Greathouse IV_, Nov 29 2024 %Y A086858 Cf. A000312, A095703. %K A086858 easy,nonn %O A086858 1,4 %A A086858 Christopher M. Tomaszewski (cmt1288(AT)comcast.net), Sep 16 2003 %E A086858 Edited by _Jon E. Schoenfield_, Sep 09 2017