A109214 - OEIS

%I #6 Nov 21 2013 12:48:43

%S 1,2,2,4,8,32,256,5888,3838976,34109301760,231888097227054080,

%T 1556059601911449331359933440,

%U 125186119679477750610733678211850458005934080,55507466796083630515105997822341552764197877620395801846452095434158080

%N Product of a(n-1) and digit reversal of a(n-2).

%C Cf. A000301 a(n) = a(n-1)*a(n-2), A004086 R(n) = digit reversal of n, A109213 a(n) = a(n-2)*R(a(n-1)).

%C The next term (a(15)) has 115 digits. [From Harvey P. Dale, Nov 14 2011]

%F a(n)=a(n-1)*R(a(n-2)).

%t a[1]=1;a[2]=2;a[n_]:=a[n]=a[n-1]*FromDigits[Reverse[IntegerDigits[a[n-2]]]]; A109214=Table[a[n], {n, 13}]

%t Transpose[NestList[{Last[#],Last[#]FromDigits[Reverse[ IntegerDigits[ First[ #]]]]}&,{1,2},13]][[1]] (* _Harvey P. Dale_, Nov 14 2011 *)

%Y Cf. A000301, A004086, A109213.

%K base,nonn

%O 1,2

%A _Zak Seidov_, Jun 22 2005

%E One more term (a(14)) from Harvey P. Dale, Nov 14 2011