A182182 a(0) = 0, a(1) = 1; for n > 1, a(n) = a(n-1) XOR a(n-2) XOR n.

0, 1, 3, 1, 6, 2, 2, 7, 13, 3, 4, 12, 4, 5, 15, 5, 26, 14, 6, 27, 9, 7, 24, 8, 8, 25, 11, 9, 30, 10, 10, 31, 53, 11, 28, 52, 12, 29, 55, 13, 18, 54, 14, 19, 49, 15, 16, 48, 16, 17, 51, 17, 22, 50, 18, 23, 61, 19, 20, 60, 20, 21, 63, 21, 106, 62, 22, 107, 57

Offset

0,3

Comments

Note that a(3n) = n.

Links

T. D. Noe, Table of n, a(n) for n = 0..1023

Eric Weisstein's World of Mathematics, XOR

Wikipedia, Bitwise operation XOR

Mathematica

t = {0, 1}; Do[AppendTo[t, BitXor[n, t[[-1]], t[[-2]]]], {n, 2, 100}]; t (* T. D. Noe, Apr 18 2012 *)
nxt[{n_, a_, b_}]:={n+1, b, BitXor[a, b, n+1]}; Transpose[NestList[nxt, {1, 0, 1}, 100]] [[2]] (* Harvey P. Dale, Aug 14 2013 *)

Prog

(Python)
prpr = 0
prev = 1
print('0, 1', end=', ')
for i in range(2, 101):
    current = prev ^ prpr ^ i
    print(current, end=", ")
    prpr = prev
    prev = current
(Haskell)
import Data.Bits (xor)
a182182 n = a182182_list !! n
a182182_list = 0 : 1 : zipWith xor [2..]
               (zipWith xor a182182_list $ tail a182182_list) :: [Integer]
-- Reinhard Zumkeller, Apr 23 2012

Crossrefs

Cf. A038712.

Sequence in context: A327438 A010467 A335320 * A158823 A184168 A122913

Adjacent sequences: A182179 A182180 A182181 * A182183 A182184 A182185

Keyword

nonn,base,look

Author

Alex Ratushnyak, Apr 17 2012

Status

approved