OFFSET
0,2
LINKS
Harry J. Smith, Table of n, a(n) for n = 0..1000
FORMULA
a(n) = A001370(2n). Results given there imply a(n) > log_4(n) + 1/2, n > 0, but we can conjecture & expect a(n) ~ 9*log_10(2)*n. - M. F. Hasler, May 18 2017
MATHEMATICA
Table[Total[IntegerDigits[4^n]], {n, 0, 60}] (* Vincenzo Librandi, Oct 08 2013 *)
PROG
(PARI) a065713(n)=sumdigits(4^n); \\ Michel Marcus, Nov 01 2013
CROSSREFS
KEYWORD
nonn,base
AUTHOR
N. J. A. Sloane, Dec 11 2001
STATUS
approved