%N Index in A002858 of the smaller of the two Ulam numbers that sum to the n-th Ulam number.
%C The first two are zero because the Ulam sequence (A002858) is initialized for those terms. The terms of the sum are in A080328 and A080329 and the indices are in A080330 and A080331.
%e The 11th Ulam number (26) is the sum of the 6th Ulam number (8) and the 10th Ulam number (18), so a(11)=6.
%Y Cf. A002858, A080328, A080329, A080331.
%A _Jud McCranie_, Feb 15 2003