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%I #15 Jul 08 2021 09:27:34
%S 0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,2,3,
%T 3,3,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,5,5,5,5,5,5,5,5,5,5,5,6,6,
%U 6,6,6,6,6,6,6,6,6,7,7,7,7,7,7,7,7,7,7,7,8,8,8,8,8,8,8,8,8,8,8,9,9
%N Highest power of 11 dividing n!.
%H Harry J. Smith, <a href="/A064458/b064458.txt">Table of n, a(n) for n = 0..1000</a>
%F a(n) = floor[n/11] + floor[n/121] + floor[n/1331] + floor[n/14641] + ....
%F a(n) = (n-A053831(n))/10. [_R. J. Mathar_, Oct 17 2010]
%t Table[t = 0; p = 11; While[s = Floor[n/p]; t = t + s; s > 0, p *= 11]; t, {n, 0, 100} ]
%t IntegerExponent[Range[0,110]!,11] (* _Harvey P. Dale_, Aug 07 2017 *)
%o (PARI) { for (n=0, 1000, a=0; p=11; while (s = n\p, a+=s; p*=11); write("b064458.txt", n, " ", a) ) } \\ _Harry J. Smith_, Sep 14 2009
%o (PARI) a(n) = valuation(n!, 11); \\ _Michel Marcus_, Apr 07 2016
%Y Cf. A011371, A054861, A054899.
%K easy,nonn
%O 0,23
%A _Robert G. Wilson v_, Oct 03 2001
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