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A199770 Self-convolution with "addition" played by bitwise XOR. 4
1, 0, 2, 6, 18, 50, 146, 426, 1282, 3810, 11394, 34082, 102338, 306658, 919874, 2759154, 8276898, 24828386, 74484386, 223444258, 670326242, 2010964770, 6032902242, 18098635298, 54295809826, 162887261410, 488661978274, 1465985458850, 4397955924386 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
LINKS
FORMULA
a(1)=1, a(n) = sum ( a(i) XOR a(n-i), i = 1 .. n-1).
MAPLE
a:= proc(n) option remember; `if`(n=0, 1, add(
Bits[Xor](a(i), a(n-1-i)), i=0..n-1))
end:
seq(a(n), n=0..35); # Alois P. Heinz, Jun 16 2018
MATHEMATICA
a[1] = 1; a[n_] := a[n] = Sum[BitXor[a[i], a[n - i]], {i, 1, n - 1}]; Table[a[n], {n, 30}]
PROG
(Haskell)
import Data.Bits (xor)
a199770 n = a199770_list !! (n-1)
a199770_list = 1 : f [1] where
f xs = y : f (y : xs) where
y = sum $ zipWith xor xs $ reverse xs :: Integer
-- Reinhard Zumkeller, Jul 15 2012
CROSSREFS
Cf. A000108 (Catalan numbers).
Sequence in context: A081154 A002900 A309087 * A204322 A196593 A248735
KEYWORD
nonn,easy
AUTHOR
Jacob A. Siehler, Nov 10 2011
STATUS
approved

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Last modified March 19 02:44 EDT 2024. Contains 370952 sequences. (Running on oeis4.)