%I #13 Apr 29 2018 02:13:10
%S 1,0,1,7,78,2392,248085,151428144
%N Number of increasing sequences of n positive integers with reciprocals adding up to an integer.
%e a(4)=7 enumerates sequences: (1,2,3,6), (2,4,5,20), (2,4,6,12), (2,3,7,42), (2,3,8,24), (2,3,9,18), and (2,3,10,15).
%Y Row sums of A280520.
%Y Cf. A006585 (adding up to 1), A156871 (nondecreasing sequences), A280517 (ordered sequences).
%K nonn,hard,more
%O 1,4
%A _Max Alekseyev_, Jan 04 2017