Number of chains in the power set lattice of an (n+3)-element set X_(n+3) of specification n^1 2^1 1, that is, n identical objects of one kind, 2 identical objects of another kind and one other kind. It is the same as the number of fuzzy subsets X_(n+3).
A107953
Number of chains in the power set lattice of an (n+3)-element set X_(n+3) of specification n^1 2^1 1, that is, n identical objects of one kind, 2 identical objects of another kind and one other kind. It is the same as the number of fuzzy subsets X_(n+3).
Terms
- a(0) =31a(1) =175a(2) =703a(3) =2415a(4) =7551a(5) =22143a(6) =61951a(7) =167167a(8) =438271a(9) =1122303a(10) =2818047a(11) =6959103a(12) =16941055a(13) =40730623a(14) =96862207a(15) =228130815a(16) =532676607a(17) =1234173951a(18) =2839543807a(19) =6491734015a(20) =14755561471a(21) =33361494015a(22) =75061264383a(23) =168124481535a(24) =375004332031a(25) =833223655423
External references
- oeis: A107953