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A080940 Smallest proper divisor of n which is a suffix of n in binary representation; a(n) = 0 if no such divisor exists. 10
0, 0, 1, 0, 1, 2, 1, 0, 1, 2, 1, 4, 1, 2, 1, 0, 1, 2, 1, 4, 1, 2, 1, 8, 1, 2, 1, 4, 1, 2, 1, 0, 1, 2, 1, 4, 1, 2, 1, 8, 1, 2, 1, 4, 1, 2, 1, 16, 1, 2, 1, 4, 1, 2, 1, 8, 1, 2, 1, 4, 1, 2, 1, 0, 1, 2, 1, 4, 1, 2, 1, 8, 1, 2, 1, 4, 1, 2, 1, 16, 1, 2, 1, 4, 1, 2, 1, 8, 1, 2, 1, 4, 1, 2, 1, 32, 1, 2, 1, 4, 1, 2, 1, 8 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

COMMENTS

By definition, identical to A006519 except that a(2^k) = 0 for all k.

a(3*2^k)=2^k and a(m)<2^k for m<3*2^k (see A007283).

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

EXAMPLE

n=6='110', divisors<6: 1='1', 2='10' and 3='11', therefore a(6)=2='10';

n=7='111', divisors<7: 1='1', therefore a(7)=1;

n=8='1000', divisors<8: 1='1', 2='10' and 4='100', therefore a(8)=0.

PROG

Haskell)

import Data.List (isPrefixOf); import Data.Function (on)

a080940 n = if null ds then 0 else head ds  where

            ds = filter ((flip isPrefixOf `on` a030308_row) n) $

                        a027751_row n

-- Reinhard Zumkeller, Mar 27 2014

CROSSREFS

Cf. A007088, A000079, A080941, A080942, A006519.

Cf. A030308, A027751.

Sequence in context: A321863 A294599 A335511 * A080941 A177405 A323302

Adjacent sequences:  A080937 A080938 A080939 * A080941 A080942 A080943

KEYWORD

nonn,base,easy

AUTHOR

Reinhard Zumkeller, Feb 25 2003

EXTENSIONS

Definition improved by Reinhard Zumkeller, Mar 27 2014

STATUS

approved

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Last modified April 22 22:19 EDT 2021. Contains 343197 sequences. (Running on oeis4.)