OFFSET
0,3
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..10000
FORMULA
a(n) = A055642(A000420(n)) = A055642(7^n) = floor(log_10(10*(7^n))). [Jonathan Vos Post, Mar 23 2012]
MATHEMATICA
Table[Length[IntegerDigits[7^n]], {n, 0, 100}] (* T. D. Noe, Mar 20 2012 *)
PROG
(Magma) [#Intseq(7^n): n in [0..67]]; // Bruno Berselli, Mar 22 2012
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Luc Comeau-Montasse, Mar 16 2012
STATUS
approved