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

Author

Jonathan Vos Post, Mar 09 2005

Keywords

• easy
• nonn

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

Crossrefs

Cf. A002467.

Programs

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 *)

Formula

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