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Number of 5's in n!.
14

%I #16 Nov 02 2022 10:29:12

%S 0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,2,1,1,0,1,0,2,0,3,3,2,2,2,4,3,1,2,

%T 2,2,2,5,1,2,5,6,5,7,5,5,8,5,6,5,2,4,7,3,3,11,5,6,5,5,3,7,6,4,7,10,3,

%U 7,8,5,10,7,3,7,13,9,10,6,9,7,14,13,1,12,8,13,13,11,10,10,12,17,17,14,15,12

%N Number of 5's in n!.

%H Seiichi Manyama, <a href="/A079690/b079690.txt">Table of n, a(n) for n = 0..10000</a>

%H <a href="/index/Fa#factorial">Index entries for sequences related to factorial numbers</a>.

%F a(n) = A034886(n) - (A027869(n) + A079680(n) + A079714(n) + A079684(n) + A079688(n) + A079691(n) + A079692(n) + A079693(n) + A079694(n)). - _Reinhard Zumkeller_, Jan 27 2008

%t DigitCount[#,10,5]&/@(Range[0,100]!) (* _Harvey P. Dale_, Sep 17 2016 *)

%Y Cf. A027869, A079714.

%Y Cf. A000142, A137579, A137580.

%K nonn,base,easy

%O 0,18

%A _Cino Hilliard_, Jan 31 2003