Triangle read by rows: T(n,k) is the number of closed binary operations on a set of n labeled elements with a closed center of size k.
A386681
Triangle read by rows: T(n,k) is the number of closed binary operations on a set of n labeled elements with a closed center of size k.
Terms
- a(0) =1a(1) =0a(2) =1a(3) =8a(4) =0a(5) =8a(6) =14580a(7) =1458a(8) =0a(9) =729a(10) =4048551936a(11) =56623104a(12) =2359296a(13) =0a(14) =1048576a(18) =56953125000a(19) =0a(20) =30517578125a(26) =0
External references
- oeis: A386681