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%I #5 Feb 11 2014 19:05:28
%S 1,2,2,4,16,2401,823543,6103515625,
%T 193630125104980427932766033374162714624,
%U 121679161406852748316898260838871037524995421354288562472420444438058627601
%N a(1) = 1; a(2) = 2; a(n) = [sum of digits of a(n-1)]^[sum of digits of a(n-2)] for n > 2.
%C The next term, a(11), has 381 digits. - _Harvey P. Dale_, Jan 08 2013
%t a[n_] := (Plus @@ IntegerDigits[a[n - 1]])^(Plus @@ IntegerDigits[a[n - 2]]); a[1] = 1; a[2] = 2; Table[ a[n], {n, 1, 10}]
%t nxt[{a_,b_}]:={b,Total[IntegerDigits[b]]^Total[IntegerDigits[a]]}; Transpose[ NestList[nxt,{1,2},10]][[1]] (* _Harvey P. Dale_, Jan 08 2013 *)
%K base,nonn
%O 1,2
%A _Joseph L. Pe_, May 09 2002
%E Edited by _Robert G. Wilson v_, May 14 2002