

A065717


Number of 6's in decimal expansion of 2^n.


11



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, 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, 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
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OFFSET

0,17


LINKS

Harry J. Smith, Table of n, a(n) for n = 0..1000


EXAMPLE

2^8 = 256 so a(8)=1.


MATHEMATICA

Table[ Count[ IntegerDigits[2^n], 6], {n, 0, 100} ]
DigitCount[#, 10, 6]&/@(2^Range[0, 100]) (* Harvey P. Dale, Feb 15 2020 *)


PROG

(PARI) a(n) = #select(x>(x==6), digits(2^n)); \\ Andrew Howroyd, Apr 25 2020
(Python)
def A065717(n):
return str(2**n).count('6') # Chai Wah Wu, Feb 14 2020


CROSSREFS

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.
Sequence in context: A060951 A115525 A241910 * A070092 A307837 A123671
Adjacent sequences: A065714 A065715 A065716 * A065718 A065719 A065720


KEYWORD

nonn,base


AUTHOR

Benoit Cloitre, Dec 04 2001


EXTENSIONS

More terms from Robert G. Wilson v, Dec 07 2001


STATUS

approved



