This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A104470 #10 Dec 25 2018 12:51:06
%S A104470 1,1,1,9,44,270,1938,15764,143776,1453302,16128420,194980478,
%T A104470 2550746400,35904118874,541097840528,8693290587030,148324680742912,
%U A104470 2678504175897990,51039398650102776,1023458322628129882
%N A104470 Tribonacci equivalent of mousetrap sequence (A002467).
%C A104470 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.
%H A104470 Harvey P. Dale, <a href="/A104470/b104470.txt">Table of n, a(n) for n = 0..449</a>
%F A104470 a(0) = a(1) = a(2) = 1; for n>2 a(n) = n*(a(n-1)+a(n-2)+a(n-3)).
%t A104470 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 *)
%Y A104470 Cf. A002467.
%K A104470 easy,nonn
%O A104470 0,4
%A A104470 _Jonathan Vos Post_, Mar 09 2005