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 A027565 #4 Mar 31 2012 12:34:58 %S A027565 1,462,52061,33952307 %N A027565 Largest number not of form k_1 k_2 .. k_n (1/k_1 + .. + 1/k_n), k_i integers >= 1. %e A027565 For n=2, the largest number not of the form k_1+k_2 with k_1>=1, k_2>=1 is 1! So a(2) = 1. For n=3 the largest number not of the form ab+bc+ca (a,b,c >= 1) is believed to be 462 (see A025052). %Y A027565 See A025052 for numbers of form ab+bc+ca (which is the case n=3), A027563 for n=4, A027564 for n=5. See also A027566. %K A027565 nonn,nice,hard %O A027565 2,2 %A A027565 _R. H. Hardin_