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Search: id:A000419
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| A000419 |
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Numbers that are the sum of 3 but no fewer nonzero squares. |
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+0
5
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| 3, 6, 11, 12, 14, 19, 21, 22, 24, 27, 30, 33, 35, 38, 42, 43, 44, 46, 48, 51, 54, 56, 57, 59, 62, 66, 67, 69, 70, 75, 76, 77, 78, 83, 84, 86, 88, 91, 93, 94, 96, 99, 102, 105, 107, 108, 110, 114, 115, 118, 120, 123, 126, 129, 131, 132, 133, 134, 138, 139, 140, 141, 142
(list; graph; listen)
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OFFSET
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1,1
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REFERENCES
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G. H. Hardy and E. M. Wright, An Introduction to the Theory of Numbers. 3rd ed., Oxford Univ. Press, 1954, p. 311.
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LINKS
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Ray Chandler, Table of n, a(n) for n=1..10000
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
Index entries for sequences related to sums of squares
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FORMULA
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Legendre: a nonnegative integer is a sum of three (or fewer) squares iff it is not of the form 4^k m with m == 7 (mod 8).
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MATHEMATICA
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Needs["NumberTheory`NumberTheoryFunctions`"]; Select[Range[150], SumOfSquaresR[3, # ] > 0 && SumOfSquaresR[2, # ] == 0 &] (*Chandler*)
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CROSSREFS
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Cf. A000378, A000408, A000415, A002828, A004215.
Sequence in context: A022155 A066157 A073159 this_sequence A115821 A115767 A058269
Adjacent sequences: A000416 A000417 A000418 this_sequence A000420 A000421 A000422
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KEYWORD
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nonn,nice,easy
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AUTHOR
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njas and J. H. Conway (conway(AT)math.princeton.edu)
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EXTENSIONS
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More terms from Arlin Anderson (starship1(AT)gmail.com)
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