OFFSET
0,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
FORMULA
a(n) = A020338(5^n).
EXAMPLE
a(1)=55 because 5^1 concatenated with 5^1 is 55.
MATHEMATICA
Table[FromDigits[Join[IntegerDigits[5^n], IntegerDigits[5^n]]], {n, 0, 20}]
PROG
(Magma) [Seqint(Intseq(5^n) cat Intseq(5^n)): n in [0..20]];
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Vincenzo Librandi, Mar 17 2012
STATUS
approved