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A137581
Number of inner zeros in decimal representation of n!.
2
0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 2, 2, 0, 1, 1, 1, 2, 3, 3, 3, 4, 1, 2, 3, 2, 3, 4, 1, 2, 0, 3, 1, 4, 1, 2, 4, 8, 4, 0, 6, 4, 4, 3, 3, 6, 1, 4, 4, 7, 6, 6, 5, 6, 5, 4, 7, 4, 6, 5, 12, 6, 7, 6, 5, 8, 7, 10, 6, 4, 9, 7, 19, 7, 7, 6, 14, 7, 11, 8, 8, 9, 11, 8, 16, 8, 7, 8, 14, 7, 8, 8, 11, 16, 10, 14, 4, 13
OFFSET
0,13
FORMULA
a(n) = A027869(n) - A027868(n);
a(A137582(n)) = 0.
a(n) = A055641(A004154(n)). - Reinhard Zumkeller, Apr 01 2015
MAPLE
A137581:= proc(n) uses StringTools;
CountCharacterOccurrences(TrimRight(SubstituteAll(
convert(n!, string), "0", " ")), " ")
end proc; # Robert Israel, May 07 2012
MATHEMATICA
f[n_] := f[n] = Block[{a = n!}, While[Mod[a, 10] == 0, a = a/10]; Count[ IntegerDigits@a, 0]]; Table[f@n, {n, 0, 98}] (* Robert G. Wilson v, Jan 28 2008 *)
Table[DigitCount[n!/10^IntegerExponent[n!, 10], 10, 0], {n, 0, 100}] (* Harvey P. Dale, Apr 10 2023 *)
PROG
(Haskell)
a137581 = a055641 . a004154 -- Reinhard Zumkeller, Apr 01 2015
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Jan 27 2008
STATUS
approved