%I #16 Apr 27 2018 17:16:17
%S 0,2,2,1,2,2,2,3,1,3,3,3,3,4,3,1,2,2,2,3,3,3,2,2,1,3,4,3,2,4,2,3,5,4,
%T 4,2,3,3,3,3,3,3,3,4,3,3,3,3,1,4,4,5,3,4,5,3,4
%N Fewest number of distinct prime factors in any product of a_1*a_2*...*a_t where n = a_1 < a_2 < ... < a_t = A006255(n) and the product is square.
%C a(n^2) = A001221(n).
%e a(14) = 4 because 14 * 15 * 16 * 18 * 20 * 21 has four distinct prime factors (2, 3, 5, and 7) and no other square product of a strictly increasing sequence starting at 14 and ending at 21 has fewer distinct prime factors.
%Y Cf. A001221, A006255, A280244.
%Y Cf. A066400, A245530.
%K nonn,more
%O 1,2
%A _Peter Kagey_, Apr 08 2018