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Search: id:A006431
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| A006431 |
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Numbers with property that their representation as sum of 4 squares is unique. |
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+0
4
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| 0, 1, 2, 3, 5, 6, 7, 8, 11, 14, 15, 23, 24, 32, 56, 96, 128, 224, 384, 512, 896, 1536, 2048, 3584, 6144, 8192, 14336, 24576, 32768, 57344, 98304, 131072, 229376, 393216, 524288, 917504, 1572864, 2097152, 3670016, 6291456, 8388608, 14680064
(list; graph; listen)
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OFFSET
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1,3
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LINKS
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Index entries for sequences related to sums of squares
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FORMULA
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Consists of 7 odd numbers plus 0 and numbers of forms 2*4^k, 6*4^k, 14*4^k, k >= 0.
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PROGRAM
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(PARI) {a(n)=if(n<1, 0, if(n<14, [1, 2, 3, 5, 6, 7, 8, 11, 14, 15, 23, 24, 32] [n], [4, 7, 12][(n+1)%3+1]*2^((n+1)\3*2-7)))} /* Michael Somos Apr 08 2006 */
(PARI) {a(n)=if(n<2, 0, if(n<15, [1, 2, 3, 5, 6, 7, 8, 11, 14, 15, 23, 24, 32] [n-1], [4, 7, 12][n%3+1]*2^(n\3*2-7)))} /* Michael Somos Apr 23 2006 */
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CROSSREFS
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{n | A002635(n) = 1}
Essentially the same as A000534.
Sequence in context: A123030 A063752 A016741 this_sequence A028229 A104452 A062877
Adjacent sequences: A006428 A006429 A006430 this_sequence A006432 A006433 A006434
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KEYWORD
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nonn,easy,nice
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AUTHOR
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David M. Bloom.
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EXTENSIONS
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More terms from James A. Sellers (sellersj(AT)math.psu.edu), Dec 24 1999
Corrected by T. D. Noe (noe(AT)sspectra.com), Jun 15 2006
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