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Search: id:A145768
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| A145768 |
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a(n) = the bitwise XOR of squares of first n natural numbers |
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+0
7
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| 1, 5, 12, 28, 5, 33, 16, 80, 1, 101, 28, 140, 37, 225, 0, 256, 33, 357, 12, 412, 37, 449, 976, 400, 993, 325, 924, 140, 965, 65, 896, 1920, 961, 1861, 908, 1692, 965, 1633, 912, 1488, 833, 1445, 668, 1292, 741, 2721, 512, 2816, 609
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Up to n=10^8, a(15) is the only zero term and a(1)=a(9) are the only terms for which a(n)=1. Can it be proved that any number can only appear a finite number of times in this sequence? [From M. F. Hasler (MHasler(AT)univ-ag.fr), Oct 20 2008]
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FORMULA
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a(n)=1^2 xor 2^2 xor ... xor n^2
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MATHEMATICA
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numberOfElements = 100; Rest[FoldList[BitXor, 0, Table[n^2, {n, 1, numberOfElements}]]]
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PROGRAM
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(PARI) an=0; for( i=1, 50, print1(an=bitxor(an, i^2), ", ")) [From M. F. Hasler (MHasler(AT)univ-ag.fr), Oct 20 2008]
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CROSSREFS
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Cf. A003815, A145827-A145829, A145830-A145831. [From M. F. Hasler (MHasler(AT)univ-ag.fr), Oct 20 2008]
Sequence in context: A073095 A078517 A128439 this_sequence A160807 A162778 A038376
Adjacent sequences: A145765 A145766 A145767 this_sequence A145769 A145770 A145771
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KEYWORD
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easy,nonn
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AUTHOR
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Vladimir Reshetnikov (v.reshetnikov(AT)gmail.com), Oct 18 2008
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