Number of permutations of 4 indistinguishable copies of 1..n with exactly 2 adjacent element pairs in decreasing order.
A151640
Number of permutations of 4 indistinguishable copies of 1..n with exactly 2 adjacent element pairs in decreasing order.
Terms
- a(0) =0a(1) =36a(2) =1828a(3) =40136a(4) =693960a(5) =11000300a(6) =168594156a(7) =2550000528a(8) =38371094416a(9) =576250000820
External references
- oeis: A151640