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A225017 Odd part of digit sum of 5^n divided by maximal possible power of 5. 9
1, 1, 7, 1, 13, 11, 19, 23, 1, 13, 1, 19, 7, 23, 17, 11, 29, 7, 1, 59, 61, 31, 67, 37, 41, 77, 79, 89, 17, 83, 91, 13, 53, 89, 103, 23, 109, 13, 31, 67, 13, 137, 29, 149, 151, 29, 7, 1, 29, 79, 151, 19, 13, 119, 127, 167, 49, 43, 211, 191, 199, 97, 187, 17, 83 (list; graph; refs; listen; history; text; internal format)
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
a(n) = A132740(A055566(n)). - Michel Marcus, Dec 10 2018
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
Sequence in context: A060393 A060394 A203810 * A268919 A040055 A317016
KEYWORD
nonn,base
AUTHOR
Vladimir Shevelev, Apr 24 2013
STATUS
approved

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Last modified March 4 09:05 EST 2024. Contains 370528 sequences. (Running on oeis4.)