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A103181 In decimal representation of n: replace all even digits with 0 and all odd digits with 1. 4
0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 10, 11, 10, 11, 10, 11, 10, 11, 10, 11, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 10, 11, 10, 11, 10, 11, 10, 11, 10, 11, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 10, 11, 10, 11, 10, 11, 10, 11, 10, 11, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 10, 11, 10, 11, 10, 11, 10, 11, 10, 11, 0, 1, 0, 1, 0, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,11

COMMENTS

a(A014263(n)) = 0. - Reinhard Zumkeller, Oct 04 2011

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 0..9999

FORMULA

n=Sum(d(k)*10^k: 0<=d(k)<10) -> a(n)=Sum((d(k) mod 2)*10^k).

EXAMPLE

199->'111': a(199)=111; 200->'000': a(200)=0;

299->'011': a(299)=11; 300->'100': a(300)=100.

PROG

(Haskell)

import Data.List (unfoldr); import Data.Tuple (swap)

a103181_list = map a103181 [0..]

a103181 n = foldl f 0 $ reverse $ unfoldr g n where

   f v d = 10 * v + mod d 2

   g x = if x == 0 then Nothing else Just $ swap $ divMod x 10

-- Reinhard Zumkeller, Oct 04 2011

(PARI) a(n)=subst(Pol(apply(k->k%2, digits(n))), 'x, 10) \\ Charles R Greathouse IV, Jul 16 2013

CROSSREFS

Cf. A000035.

Sequence in context: A004451 A004499 A020509 * A100813 A085209 A085217

Adjacent sequences:  A103178 A103179 A103180 * A103182 A103183 A103184

KEYWORD

nonn,base,easy

AUTHOR

Reinhard Zumkeller, Mar 18 2005

STATUS

approved

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Last modified April 9 14:25 EDT 2020. Contains 333355 sequences. (Running on oeis4.)