Number of permutations of n>1 having exactly 3 points P on the boundary of their bounding square.

A208528

Number of permutations of n>1 having exactly 3 points P on the boundary of their bounding square.

Terms

    a(0) =0a(1) =4a(2) =16a(3) =72a(4) =384a(5) =2400a(6) =17280a(7) =141120a(8) =1290240a(9) =13063680a(10) =145152000a(11) =1756339200a(12) =22992076800a(13) =323805081600

External references