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A079135 Number of 7's in n# (n primorial) = 7's in A002110(n). 1

%I

%S 0,0,0,0,0,0,0,0,1,0,0,2,1,2,1,3,2,3,3,2,2,5,4,5,5,3,2,6,9,4,3,10,7,2,

%T 4,2,13,2,5,4,6,9,6,6,9,7,10,9,11,10,8,5,5,7,6,10,16,10,14,12,14,10,

%U 16,13,10,12,14,13,16,17,13,20,14,11,12,8,10,15,17,9,16,15,26,21,18,19,20,28

%N Number of 7's in n# (n primorial) = 7's in A002110(n).

%H Vincenzo Librandi, <a href="/A079135/b079135.txt">Table of n, a(n) for n = 2..1000</a>

%t DigitCount[#, 10, 7]&/@Rest[FoldList[Times, 1, Prime[Range[100]]]] (* _Vincenzo Librandi_, Apr 07 2014 *)

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

%Y Cf. A002110.

%K easy,nonn

%O 2,12

%A _Cino Hilliard_, Feb 03 2003

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Last modified January 17 16:53 EST 2019. Contains 319235 sequences. (Running on oeis4.)