OFFSET
0,2
COMMENTS
Limit a(n+1)/a(n) = 3.
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 0..1000
EXAMPLE
Given a(0)=1, a(1)=2, illustrate XOR convolution for the initial terms.
a(2) = 1 XOR 2 + 2 XOR 1 = 3 + 3 = 6;
a(3) = 1 XOR 6 + 2 XOR 2 + 6 XOR 1 = 7 + 0 + 7 = 14;
a(4) = 1 XOR 14 + 2 XOR 6 + 6 XOR 2 + 14 XOR 1 = 15 + 4 + 4 + 15 = 38; ...
PROG
(PARI) {a(n)=if(n<2, n+1, sum(k=0, n-1, bitxor(a(k), a(n-k-1))))}
(Haskell)
import Data.Bits (xor)
a192484 n = a192484_list !! n
a192484_list = 1 : 2 : f [2, 1] where
f xs = y : f (y : xs) where
y = sum $ zipWith xor xs $ reverse xs :: Integer
-- Reinhard Zumkeller, Jul 15 2012
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jul 02 2011
STATUS
approved