Triangle read by rows: T(m,l) = number of labeled covers of size l of a finite set of m unlabeled elements (m >= 1, 1 <= l <= 2^m - 1).
A133709
Triangle read by rows: T(m,l) = number of labeled covers of size l of a finite set of m unlabeled elements (m >= 1, 1 <= l <= 2^m - 1).
Terms
- a(0) =1a(1) =1a(2) =3a(3) =3a(4) =1a(5) =7a(6) =35a(7) =140a(8) =420a(9) =840a(10) =840a(11) =1a(12) =12a(13) =131a(14) =1435a(15) =15225a(16) =150570a(17) =1351770a(18) =10810800a(19) =75675600a(20) =454053600a(21) =2270268000a(22) =9081072000a(23) =27243216000a(24) =54486432000a(25) =54486432000a(26) =1a(27) =18a(28) =347a(29) =7693
External references
- oeis: A133709