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%I #28 Apr 25 2020 13:32:55
%S 0,0,0,0,1,0,1,0,1,0,0,0,1,0,1,1,2,0,1,0,1,0,0,1,2,0,2,0,2,1,0,1,2,0,
%T 1,1,3,0,1,0,2,0,1,1,2,0,3,0,3,1,2,1,2,0,0,3,1,0,1,2,4,1,3,1,3,1,4,2,
%U 1,1,1,3,6,1,1,3,2,2,3,2,4,1,2,4,3,6,3,2,2,4,0,1,4,0,3,4,3,3,2,3,5
%N Number of 6's in decimal expansion of 2^n.
%H Harry J. Smith, <a href="/A065717/b065717.txt">Table of n, a(n) for n = 0..1000</a>
%e 2^8 = 256 so a(8)=1.
%t Table[ Count[ IntegerDigits[2^n], 6], {n, 0, 100} ]
%t DigitCount[#,10,6]&/@(2^Range[0,100]) (* _Harvey P. Dale_, Feb 15 2020 *)
%o (PARI) a(n) = #select(x->(x==6), digits(2^n)); \\ _Andrew Howroyd_, Apr 25 2020
%o (Python)
%o def A065717(n):
%o return str(2**n).count('6') # _Chai Wah Wu_, Feb 14 2020
%Y Cf. 0's A027870, 1's A065712, 2's A065710, 3's A065714, 4's A065715, 5's A065716, 7's A065718, 8's A065719, 9's A065744.
%K nonn,base
%O 0,17
%A _Benoit Cloitre_, Dec 04 2001
%E More terms from _Robert G. Wilson v_, Dec 07 2001
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