%I #8 Oct 04 2019 07:52:53
%S 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13,14,14,15
%N Duplicate of A008619.
%K dead
%O 1,3