A123298 a(n) = number of incongruent restricted disjoint covering systems (IRDCS) of length n. An IRDCS of length n is a sequence of n integers s(1),...,s(n) with the property that if s(i)=m for some m then the other members of the sequence with value m are precisely s(i+km) for all k such that i+km is in [1,n] and further such that any integer appearing in the sequence appears at least twice. For example the two IRDCS of length n are 6,9,3,4,5,3,6,4,3,5,9 and its reverse.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 4, 6, 18, 14, 26, 84, 88, 46, 176, 380, 812, 844, 1770, 2164, 5554, 9244, 25384, 62092, 68176, 85762, 304892, 855072, 1229050, 1805096