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 A212087 Number of (w,x,y,z) with all terms in {1,...,n} and w^2+x^2=y^2+z^2. 4
 0, 1, 6, 15, 28, 45, 66, 95, 132, 173, 210, 267, 320, 385, 458, 523, 600, 693, 786, 899, 1000, 1109, 1226, 1367, 1492, 1629, 1778, 1931, 2084, 2269, 2426, 2615, 2812, 3013, 3222, 3427, 3624, 3857, 4094, 4335, 4564, 4841, 5082, 5379, 5656, 5913 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS For a guide to related sequences, see A211795. LINKS MATHEMATICA t = Compile[{{n, _Integer}}, Module[{s = 0}, (Do[If[w^2 + x^2 == y^2 + z^2, s = s + 1], {w, 1, #}, {x, 1, #}, {y, 1, #}, {z, 1, #}] &[n]; s)]]; Map[t[#] &, Range[0, 60]] (* A212087 *) (* Peter J. C. Moses, Apr 13 2012 *) CROSSREFS Cf. A211795. Sequence in context: A096892 A000384 A164000 * A301292 A134978 A115742 Adjacent sequences:  A212084 A212085 A212086 * A212088 A212089 A212090 KEYWORD nonn AUTHOR Clark Kimberling, May 02 2012 STATUS approved

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Last modified December 11 04:29 EST 2018. Contains 318049 sequences. (Running on oeis4.)