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A179081 Parity of sum of digits of n. 11
0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
a(n) = A000035(A007953(n));
characteristic function of numbers with an odd sum of digits in their decimal representation:
a(A054684(n)) = 1; a(A054683(n)) = 0;
a(A179083(n)) = a(A179085(n)) = 1;
a(A179082(n)) = a(A179084(n)) = 0.
LINKS
FORMULA
a(n) = if n<10 then (n mod 2) else a([n/10]) XOR (n mod 2).
EXAMPLE
a(789) = (7+8+9) mod 2 = 0;
a(790) = (7+9+0) mod 2 = 0;
a(791) = (7+9+1) mod 2 = 1.
MATHEMATICA
Array[Mod[Total[IntegerDigits[#]], 2]&, 110, 0] (* Harvey P. Dale, Feb 20 2013 *)
PROG
(PARI) a(n) = vecsum(digits(n)) % 2 \\ Jeppe Stig Nielsen, Jan 06 2018
CROSSREFS
Sequence in context: A327532 A073445 A285589 * A113217 A189219 A189008
KEYWORD
base,nonn
AUTHOR
Reinhard Zumkeller, Jun 28 2010
STATUS
approved

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Last modified March 19 04:58 EDT 2024. Contains 370952 sequences. (Running on oeis4.)