OFFSET
1,1
COMMENTS
a(n) = 5^d(n), with
d(n) = {1, 2, 4, 5, 7, 8, 10, 11, 12, 14, 15, 17, 18, 20, 21, 22, 24, 25, 27, 28}.
If we redefine the sequence as a(n) = the highest power of 5 less than 10^n, then keyword "base" may be omitted.
d(n) = A066344(n). - Zak Seidov, Oct 01 2010
MATHEMATICA
d[n_]=Floor@Log[5, 10^n]; a[n_]=5^d[n]
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Zak Seidov, Sep 29 2010
STATUS
approved