%I #15 Sep 20 2021 19:02:02

%S 0,1,1,2,2,0,2,0,-2,-2,4,6,10,60,50,110,5500,5390,10890,58697100,

%T 58686210,117383310,6888781581155100,6888781463771790,

%U 13777563044926890,94910620919839581404684194433100,94910620919839567627121149506210

%N Sequence based on repeating in turn the subtract, add and multiply operations on the previous 2 terms, starting with 0, 1.

%C After a(16) the sequence entries end 100, 90, 90, 100, 10, 10, 100, 90, 90, ... . - _Jon Perry_, Oct 29 2014

%F For n > 2,

%F If n mod 3 = 0, a(n) = a(n-1) - a(n-2),

%F If n mod 3 = 1, a(n) = a(n-1) + a(n-2),

%F If n mod 3 = 2, a(n) = a(n-1) x a(n-2),

%F a(1) = 0, a(2) = 1.

%t nxt[{n_,a_,b_}]:={n+1,b,Which[Mod[n+1,3]==0,b-a,Mod[n+1,3] == 1,a+b,True,a*b]}; NestList[nxt,{2,0,1},30][[All,2]] (* _Harvey P. Dale_, Sep 20 2021 *)

%K sign,easy

%O 1,4

%A _Stuart E Anderson_, Oct 07 2014

%E More terms from _Colin Barker_, Oct 08 2014

%E Edited: Name changed and keyword easy added - _Wolfdieter Lang_, Oct 29 2014

%E Changed name. - _Jon Perry_, Oct 29 2014