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A065712 Number of 1's in decimal expansion of 2^n. 15
1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 2, 1, 0, 1, 1, 1, 0, 2, 0, 1, 2, 0, 1, 2, 1, 0, 0, 3, 0, 1, 1, 0, 1, 3, 1, 3, 0, 3, 1, 1, 1, 2, 2, 2, 2, 0, 1, 3, 1, 0, 4, 4, 0, 3, 1, 3, 0, 3, 3, 0, 2, 2, 3, 6, 3, 1, 0, 2, 3, 3, 5, 1, 1, 5, 3, 1, 2, 5, 1, 4, 2, 2, 5, 2, 0, 5, 3, 1, 6, 2, 2, 4, 5, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,18
COMMENTS
2^17 = 131072 so a(17)=2.
LINKS
MATHEMATICA
Table[ Count[ IntegerDigits[2^n], 1], {n, 0, 100} ]
Table[DigitCount[2^n, 10, 1], {n, 0, 120}] (* Harvey P. Dale, Aug 15 2014 *)
PROG
(PARI) Count(x, d)= { local(c=0, f); while (x>9, f=x-10*(x\10); if (f==d, c++); x\=10); if (x==d, c++); return(c) }
{ for (n=0, 1000, a=Count(2^n, 1); write("b065712.txt", n, " ", a) ) } \\ Harry J. Smith, Oct 26 2009
(PARI) a(n) = #select(x->(x==1), digits(2^n)); \\ Michel Marcus, Jun 15 2018
(Python)
def A065712(n):
return str(2**n).count('1') # Chai Wah Wu, Feb 14 2020
CROSSREFS
Cf. 0's A027870, 3's A065714, 4's A065715, 5's A065716, 6's A065717, 7's A065718, 8's A065719, 9's A065744.
Sequence in context: A024359 A354512 A088705 * A153172 A242498 A321927
KEYWORD
nonn,base
AUTHOR
Benoit Cloitre, Dec 04 2001
EXTENSIONS
More terms from Robert G. Wilson v, Dec 07 2001
STATUS
approved

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Last modified March 18 21:02 EDT 2024. Contains 370951 sequences. (Running on oeis4.)