OFFSET
0,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
FORMULA
a(n) = A020338(3^n). - Bruno Berselli, Mar 14 2012
EXAMPLE
a(1)=33 because 3^1 concatenated with 3^1 is 33.
MATHEMATICA
Table[FromDigits[Join[IntegerDigits[3^n], IntegerDigits[3^n]]], {n, 0, 18}] (* Bruno Berselli, Mar 14 2012 *)
Table[3^n 10^IntegerLength[3^n]+3^n, {n, 0, 20}] (* Harvey P. Dale, May 27 2019 *)
PROG
(Magma) [Seqint(Intseq(3^n) cat Intseq(3^n)): n in [0..18]]; // Bruno Berselli, Mar 14 2012
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Vincenzo Librandi, Mar 14 2012
STATUS
approved