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A226532
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If n = Product_{i>0} prime(i)^e(i), then a(n) = Product_{i>0} prime(i)^(XOR_{j>=i} e(j)), where XOR is bitwise XOR.
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3
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1, 2, 6, 4, 30, 3, 210, 8, 36, 15, 2310, 24, 30030, 105, 5, 16, 510510, 72, 9699690, 120, 35, 1155, 223092870, 12, 900, 15015, 216, 840, 6469693230, 10, 200560490130, 32, 385, 255255, 7, 9, 7420738134810, 4849845, 5005, 60, 304250263527210, 70, 13082761331670030, 9240, 1080, 111546435, 614889782588491410
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OFFSET
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1,2
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COMMENTS
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This sequence is a permutation of the natural numbers.
The powers of 2 are the fixed points of this sequence.
a(prime(i)) = A002110(i) for any i > 0.
a(i^2) = a(i)^2 for any i > 0.
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LINKS
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EXAMPLE
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a(50) = a(2^1 * 3^0 * 5^2)
= 2^xor(1,0,2) * 3^xor(0,2) * 5^xor(2)
= 2^3 * 3^2 * 5^2
= 1800.
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PROG
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(Perl) See link.
(Haskell)
import Data.Bits (xor)
a226532 n = product $ zipWith (^)
a000040_list (scanr1 xor $ a067255_row n :: [Integer])
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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