A108188 a(n) = (n-1)*(a(n-1)+a(n-2)+a(n-3)).

0, 1, 1, 6, 32, 195, 1398, 11375, 103744, 1048653, 11637720, 140691287, 1840531920, 25907192051, 390437813612, 6272783063745, 107026049110528, 1932717589794045, 36828295595429724, 738492745452351643

Offset

1,4

Comments

Derangement-type sequence like A000166 on the tribonacci A000213.

Links

Table of n, a(n) for n=1..20.

Mathematica

F[1] = 0; F[2] = 1; F[3] = 1; F[n__] := F[n] = (n - 1)*(F[n - 1] + F[n - 2] + F[n - 3]) a = Table[F[n], {n, 1, 25}]
RecurrenceTable[{a[1]==0, a[2]==a[3]==1, a[n]==(n-1)(a[n-1]+a[n-2]+a[n-3])}, a, {n, 20}] (* Harvey P. Dale, Oct 26 2019 *)

Crossrefs

Cf. A000166, A000213.

Sequence in context: A302734 A319228 A216441 * A020058 A146557 A020013

Adjacent sequences: A108185 A108186 A108187 * A108189 A108190 A108191

Keyword

nonn

Author

Roger L. Bagula, Jun 14 2005

Status

approved