A104470 Tribonacci equivalent of mousetrap sequence (A002467).

1, 1, 1, 9, 44, 270, 1938, 15764, 143776, 1453302, 16128420, 194980478, 2550746400, 35904118874, 541097840528, 8693290587030, 148324680742912, 2678504175897990, 51039398650102776, 1023458322628129882

Offset

0,4

Comments

The mousetrap sequence (A002467) can be defined in a Fibonacci-like way as: a(0) = a(1) = 1; for n>1 a(n) = n*(a(n-1)+a(n-2)). The current sequence is thus the tribonacci equivalent of that.

Links

Harvey P. Dale, Table of n, a(n) for n = 0..449

Formula

a(0) = a(1) = a(2) = 1; for n>2 a(n) = n*(a(n-1)+a(n-2)+a(n-3)).

Mathematica

RecurrenceTable[{a[0]==a[1]==a[2]==1, a[n]==n(a[n-1]+a[n-2]+a[n-3])}, a, {n, 20}] (* Harvey P. Dale, Dec 25 2018 *)

Crossrefs

Cf. A002467.

Sequence in context: A099867 A228603 A297491 * A282722 A084016 A221508

Adjacent sequences: A104467 A104468 A104469 * A104471 A104472 A104473

Keyword

easy,nonn

Author

Jonathan Vos Post, Mar 09 2005

Status

approved