%C a(n+1) = a(n) written in base 3 and read as if in base 27 (and recorded in base 10).
%C Number of distinct n-ary operators in a ternary logic. - _Ross Drewe_, Feb 13 2008
%C The next term has 116 digits. - _Harvey P. Dale_, Mar 28 2019
%F a(n) =a(n-1)^3.
%t NestList[#^3&,3,5] (* _Harvey P. Dale_, Mar 28 2019 *)
%Y Cf. A001146, A023365.
%A _Henry Bottomley_, Jul 12 2000
%E Next term is too big to include.