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A004433
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Numbers that are the sum of 4 distinct nonzero squares: of form w^2+x^2+y^2+z^2 with 0<w<x<y<z.
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2
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30, 39, 46, 50, 51, 54, 57, 62, 63, 65, 66, 70, 71, 74, 75, 78, 79, 81, 84, 85, 86, 87, 90, 91, 93, 94, 95, 98, 99, 102, 105, 106, 107, 109, 110, 111, 113, 114, 116, 117, 118, 119, 120, 121, 122, 123, 125, 126, 127, 129, 130, 131, 133, 134, 135, 137
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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LINKS
| T. D. Noe, Table of n, a(n) for n=1..1000
Index entries for sequences related to sums of squares
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EXAMPLE
| 30 = 1^2+2^2+3^2+4^2.
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MATHEMATICA
| data = Flatten[ DeleteCases[ FindInstance[ w^2 + x^2 + y^2 + z^2 == # && 0 < w < x < y < z < #, {w, x, y, z}, Integers] & /@ Range[137], {}], 1]; w^2 + x^2 + y^2 + z^2 /. data (* From Ant King, Oct 17 2010 *)
Select[Union[Total[#^2]&/@Subsets[Range[10], {4}]], #<=137&] (* From Harvey P. Dale, July 03 2011 *)
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CROSSREFS
| Cf. A001944, A001995.
Sequence in context: A051657 A130038 A001995 * A025376 A152616 A103250
Adjacent sequences: A004430 A004431 A004432 * A004434 A004435 A004436
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KEYWORD
| nonn,easy,nice
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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