OFFSET
0,3
COMMENTS
Does the sequence contain every prime greater than 5?
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..10000 (terms n = 0..999 from Peter J. C. Moses)
FORMULA
MAPLE
a:= proc(n) local m, r; m, r:= 0, 5^n;
while r>0 do m:= m+irem(r, 10, 'r') od;
while irem(m, 2, 'r')=0 do m:=r od;
while irem(m, 5, 'r')=0 do m:=r od; m
end:
seq(a(n), n=0..80); # Alois P. Heinz, Apr 24 2013
MATHEMATICA
Map[#/(2^IntegerExponent[#, 2] 5^IntegerExponent[#, 5])&[Total[ IntegerDigits[5^#]]]&, Range[0, 99]] (* Peter J. C. Moses, Apr 24 2013 *)
PROG
(PARI) a(n) = my(x = sumdigits(5^n)); x/5^valuation(x, 5) >> valuation(x, 2); \\ Michel Marcus, Dec 10 2018
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Vladimir Shevelev, Apr 24 2013
STATUS
approved