249698domain: NAppears in sequencesGaps of 6 in sequence A038593 (lower terms).at n=19A038651Number of difference sets of subsets of {1,2,...,n}, i.e., the size of {D(A) : A subset [n] }, where D(A)={a_i-a_j : a_i>a_j and a_i,a_j in A}.at n=26A067247