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 A156870 #7 Mar 12 2017 15:12:49 %S A156870 1,4,18,168,3648,298165,159628076 %N A156870 Number of nondecreasing sequences of 2n positive integers with reciprocals adding up to n (1 <= n). %C A156870 Conjecture: A156869(2n + m, n + m) = a(n) if and only if m >= 0. %e A156870 For n = 2, the a(2) = 4 sequences are (1, 2, 3, 6), (1, 2, 4, 4), (1, 3, 3, 3) and (2, 2, 2, 2) because 1/1 + 1/2 + 1/3 + 1/6 = 1/1 + 1/2 + 1/4 + 1/4 = 1/1 + 1/3 + 1/3 + 1/3 = 1/2 + 1/2 + 1/2 + 1/2 = 2. %Y A156870 a(n) = A156869(2n, n). %K A156870 more,nonn %O A156870 1,2 %A A156870 _Jens Voß_, Feb 17 2009 %E A156870 a(6) from _M. F. Hasler_, Feb 21 2009 %E A156870 a(7) from _Max Alekseyev_, Jan 04 2017