OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
FORMULA
a(n) = A055642(A000302(n)) = A055642(4^n) = floor(log_10(10*(4^n))). - Jonathan Vos Post, Mar 22 2012
EXAMPLE
a(4) = 3 because 4^4 = 256, which has 3 digits.
a(5) = 4 because 4^5 = 1024, which has 4 digits.
MAPLE
a:= n-> length(4^n): seq(a(n), n=0..100); # Alois P. Heinz, Mar 22 2012
MATHEMATICA
Table[Length[IntegerDigits[4^n]], {n, 0, 68}] (* Bruno Berselli, Mar 22 2012 *)
PROG
(Magma) [#Intseq(4^n): n in [0..68]]; // Bruno Berselli, Mar 22 2012
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Luc Comeau-Montasse, Mar 21 2012
STATUS
approved