0,4

a(n) =n^n-C(2n, n)+n =A000312(n)-A045992(n)

a(3)=10 since the mappings of (1,2,3) to (1,2,1), (1,3,1), (1,3,2), (2,1,2), (2,1,3), (2,3,1), (2,3,2), (3,1,2), (3,1,3), and (3,2,3) all reverse direction

Cf. A000312, A000984, A001700, A045992.

Sequence in context: A064092 A121973 A006409 this_sequence A033714 A131521 A113373

Adjacent sequences: A056171 A056172 A056173 this_sequence A056175 A056176 A056177

nonn

Henry Bottomley (se16(AT)btinternet.com), Jul 27 2000