A268643 Number of 1's in decimal representation of n.

0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1

Offset

0,12

Links

Robert Israel, Table of n, a(n) for n = 0..10000

Formula

a(n) = a(floor(n/10)) + 1 if n == 1 (mod 10), otherwise a(n) = a(floor(n/10)).

G.f. g(x) satisfies g(x) = x/(1-x^10) + (1-x^10)*g(x^10)/(1-x).

Maple

f:= n -> numboccur(1, convert(n, base, 10)):
map(f, [$0..100]);

Mathematica

DigitCount[Range[0, 120], 10, 1] (* Harvey P. Dale, Apr 08 2018 *)

Prog

(Python)
def A268643(n): return str(n).count('1') # Chai Wah Wu, Dec 23 2022

Crossrefs

Second column of A100910.

Sequence in context: A172090 A037912 A056980 * A005094 A121372 A359432

Adjacent sequences: A268640 A268641 A268642 * A268644 A268645 A268646

Keyword

nonn,base

Author

Robert Israel, Feb 09 2016

Status

approved