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Greatest proper divisor of n which is a suffix of n in binary representation; a(n) = 0 if no such divisor exists.
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%I #7 Mar 27 2014 18:18:15

%S 0,0,1,0,1,2,1,0,1,2,1,4,1,2,3,0,1,2,1,4,1,2,1,8,1,2,3,4,1,6,1,0,1,2,

%T 1,4,1,2,3,8,1,2,1,4,5,2,1,16,1,2,3,4,1,6,1,8,1,2,1,12,1,2,7,0,1,2,1,

%U 4,1,2,1,8,1,2,3,4,1,6,1,16,1,2,1,4,5,2,3,8,1,10,1,4,1,2,1,32,1,2,3,4,1,6,1

%N Greatest proper divisor of n which is a suffix of n in binary representation; a(n) = 0 if no such divisor exists.

%C a(n)=0 iff n=2^k (A000079);

%H Reinhard Zumkeller, <a href="/A080941/b080941.txt">Table of n, a(n) for n = 1..10000</a>

%e n=30='11110', divisors<30: 1='1', 2='10', 3='11', 5='101', 6='110', 10='1010' and 15='1111', therefore a(30)=2='10';

%e n=31='11111', divisors<31: 1='1', therefore a(31)=1;

%e n=32='100000', divisors<32: 1='1', 2='10', 4='100', 8='1000' and 16='10000', therefore a(32)=0.

%o (Haskell)

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

%o a080941 n = if null ds then 0 else head ds where

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

%o reverse $ a027751_row n

%o -- _Reinhard Zumkeller_, Mar 27 2014

%Y Cf. A007088, A080940, A080942.

%Y Cf. A030308, A027751.

%K nonn,base

%O 1,6

%A _Reinhard Zumkeller_, Feb 25 2003

%E Definition improved by _Reinhard Zumkeller_, Mar 27 2014