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A063401 a(n) = a(n-1)*a(n-2)*a(n-3) with a(0)=1, a(1)=2, a(2)=2.

%I A063401 #12 Sep 05 2021 13:45:42
%S A063401 1,2,2,4,16,128,8192,16777216,17592186044416,
%T A063401 2417851639229258349412352,
%U A063401 713623846352979940529142984724747568191373312,30354201441027016733116592294117482916287606860189680019559568902170379456331382784
%N A063401 a(n) = a(n-1)*a(n-2)*a(n-3) with a(0)=1, a(1)=2, a(2)=2.
%H A063401 Harry J. Smith, <a href="/A063401/b063401.txt">Table of n, a(n) for n=0,...,15</a>
%F A063401 a(n) = 2^A000073(n+1).
%e A063401 a(6) = 128*16*4 = 8192.
%t A063401 a0=1;a1=1;a2=2;lst={a0,a1,a2};Do[AppendTo[lst,a=a0*a1*a2]; a0=a1;a1=a2;a2=a, {n,12}];lst (* _Vladimir Joseph Stephan Orlovsky_, Nov 18 2009 *)
%t A063401 RecurrenceTable[{a[0]==1,a[1]==a[2]==2,a[n]==a[n-1]a[n-2]a[n-3]},a,{n,12}] (* _Harvey P. Dale_, Sep 05 2021 *)
%o A063401 (PARI) { for (n = 0, 15, if (n>2, a=a1*a2*a3; a3=a2; a2=a1; a1=a, if (n==0, a=a3=1; a1=a2=2, a=2)); write("b063401.txt", n, " ", a) ) } \\ _Harry J. Smith_, Aug 20 2009
%Y A063401 Cf. A000301, A000308.
%K A063401 nonn
%O A063401 0,2
%A A063401 _Henry Bottomley_, Jul 16 2001
%E A063401 Definition corrected to a(1)=2 by _Harry J. Smith_, Aug 20 2009