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 A040173 #16 Feb 16 2025 08:32:38 %S A040173 1,3,1,3,19,53,103,4111,78293,29401,4462987,9830941,284397779 %N A040173 Numerator of probability that 2 elements of S_n chosen at random (with replacement) generate S_n. %H A040173 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SymmetricGroup.html">Symmetric Group.</a> %e A040173 Values for n=1,2,3,... are 1, 3/4, 1/2, 3/8, 19/40, 53/120, 103/168, 4111/6720, 78293/120960, ... %Y A040173 Probability is A040173/A040174 = A040175/n!. %K A040173 nonn,nice,frac,more %O A040173 1,2 %A A040173 _Dan Hoey_ %E A040173 a(10)-a(13) from _Stephen A. Silver_, Feb 21 2013