OFFSET
1,2
COMMENTS
First differences of A263475.
LINKS
Hiroaki Yamanouchi, Table of n, a(n) for n = 1..50
FORMULA
MATHEMATICA
Last /@ Tally@ IntegerLength@ Select[Range@ 1000000, FixedPoint[Times @@ IntegerDigits@ # &, #] == 8 &] (* Michael De Vlieger, Oct 21 2015 *)
PROG
(PARI) t(k) = {while(k>9, k=prod(i=1, #k=digits(k), k[i])); k}
a(n) = sum(i=10^(n-1), 10^n - 1, if(t(i) == 8, 1, 0)); \\ Altug Alkan, Oct 19 2015
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Martin Renner, Oct 19 2015
EXTENSIONS
a(9)-a(23) from Hiroaki Yamanouchi, Oct 25 2015
STATUS
approved