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A100281
a(n) = A099896(A099896(n)).
4
0, 1, 2, 3, 5, 4, 7, 6, 10, 11, 8, 9, 15, 14, 13, 12, 21, 20, 23, 22, 16, 17, 18, 19, 31, 30, 29, 28, 26, 27, 24, 25, 42, 43, 40, 41, 47, 46, 45, 44, 32, 33, 34, 35, 37, 36, 39, 38, 63, 62, 61, 60, 58, 59, 56, 57, 53, 52, 55, 54, 48, 49, 50, 51, 84, 85, 86, 87, 81, 80, 83, 82, 94
OFFSET
0,3
COMMENTS
Permutation of the natural numbers with inverse A100282;
A064707(n) = a(n) for n<64.
FORMULA
a(n) = n XOR floor(n/4) XOR floor(n/16). - Ivan Neretin, Sep 06 2017
PROG
(Python)
def A100281(n): return n^(m:=n>>2)^(m>>2) # Chai Wah Wu, Jan 19 2023
CROSSREFS
KEYWORD
nonn,look
AUTHOR
Reinhard Zumkeller, Nov 11 2004
STATUS
approved