%I #6 May 11 2019 18:31:53
%S 1,1,3,6,11,8,26,50,79,121,195,265,478,742,1269,1914,2929,4462,6825,
%T 10309,16324,24633,37213,56828,84482
%N Number of compositions of n with distinct circular differences.
%C A composition of n is a finite sequence of positive integers summing to n.
%C The circular differences of a composition c of length k are c_{i + 1} - c_i for i < k and c_1 - c_i for i = k. For example, the circular differences of (1,2,1,3) are (1,-1,2,-2), which are distinct, so (1,2,1,3) is counted under a(7).
%H Gus Wiseman, <a href="/A325325/a325325.txt">Sequences counting and ranking integer partitions by the differences of their successive parts.</a>
%e The a(1) = 1 through a(7) = 26 compositions:
%e (1) (2) (3) (4) (5) (6) (7)
%e (12) (13) (14) (15) (16)
%e (21) (31) (23) (24) (25)
%e (112) (32) (42) (34)
%e (121) (41) (51) (43)
%e (211) (113) (114) (52)
%e (122) (141) (61)
%e (131) (411) (115)
%e (212) (124)
%e (221) (133)
%e (311) (142)
%e (151)
%e (214)
%e (223)
%e (232)
%e (241)
%e (313)
%e (322)
%e (331)
%e (412)
%e (421)
%e (511)
%e (1213)
%e (1312)
%e (2131)
%e (3121)
%t Table[Length[Select[Join@@Permutations/@IntegerPartitions[n],UnsameQ@@Differences[Append[#,First[#]]]&]],{n,15}]
%Y Cf. A000079, A000740, A008965, A242882, A325545, A325549, A325553, A325558, A325589, A325591.
%K nonn,more
%O 1,3
%A _Gus Wiseman_, May 10 2019