login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A178910 Binary XOR of divisors of n. 19
1, 3, 2, 7, 4, 6, 6, 15, 11, 12, 10, 14, 12, 10, 8, 31, 16, 29, 18, 28, 16, 30, 22, 30, 29, 20, 16, 18, 28, 24, 30, 63, 40, 48, 32, 49, 36, 54, 40, 60, 40, 48, 42, 54, 44, 58, 46, 62, 55, 39, 32, 36, 52, 48, 56, 34, 40, 36, 58, 56, 60, 34, 38, 127, 72, 120, 66, 112, 80, 96, 70 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

If 2^k <= n < 2^(k+1), then also 2^k <= a(n) < 2^(k+1), since any proper divisor of n is < 2^k.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..8191

PROG

(PARI) a(n)=local(ds, r); ds=divisors(n); for(k=1, #ds, r=bitxor(r, ds[k])); r

(Haskell)

import Data.Bits (xor)

a178910 = foldl1 xor . a027750_row :: Integer -> Integer

-- Reinhard Zumkeller, Nov 17 2012

CROSSREFS

Cf. A000203, A178908, A178911, A003987.

Cf. A027750, A072594; subsequences A028982 (odd), A028982 (even).

Sequence in context: A341916 A344878 A344875 * A182651 A175055 A085168

Adjacent sequences:  A178907 A178908 A178909 * A178911 A178912 A178913

KEYWORD

base,nonn,look

AUTHOR

Franklin T. Adams-Watters, Jun 22 2010

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 6 00:46 EDT 2021. Contains 346493 sequences. (Running on oeis4.)