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Number of 9's in n# (n primorial) = 9's in A002110(n).
1

%I #12 Feb 09 2018 21:49:07

%S 0,0,0,0,0,0,0,4,1,2,1,0,0,0,2,2,2,3,2,5,4,3,4,1,2,2,4,7,7,4,6,6,3,7,

%T 4,8,7,5,11,11,8,7,14,8,8,13,10,8,5,16,6,8,10,5,14,14,14,12,15,15,15,

%U 11,7,12,14,13,18,15,17,10,17,13,18,14,13,16,20,16,14,17,19,19,18,22,13,19

%N Number of 9's in n# (n primorial) = 9's in A002110(n).

%H Vincenzo Librandi, <a href="/A079163/b079163.txt">Table of n, a(n) for n = 2..1000</a>

%t DigitCount[#, 10, 9]&/@Rest[FoldList[Times, 1, Prime[Range[90]]]] (* _Harvey P. Dale_, Dec 07 2011 *)

%o (PARI) See program in Number of 0's in n#

%Y Cf. A002110.

%K easy,nonn

%O 2,8

%A _Cino Hilliard_, Feb 03 2003