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A198385
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Second of a triple of squares in arithmetic progression.
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16
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25, 100, 169, 225, 289, 400, 625, 676, 625, 841, 900, 1156, 1369, 1225, 1681, 1521, 1600, 2500, 2025, 2704, 2601, 2500, 3721, 2809, 3025, 4225, 3364, 3600, 4225, 4225, 4225, 4624, 5625, 5476, 7225, 4900, 6724, 6084, 5329, 5625, 6400, 7225, 7225, 7225, 7921
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history;
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OFFSET
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1,1
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LINKS
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Ray Chandler, Table of n, a(n) for n = 1..10000
Keith Conrad, Arithmetic progressions of three squares
Reinhard Zumkeller, Table of initial values
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FORMULA
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a(n) = A198389(n)^2.
a(n) - A198384(n) = A198386(n) - a(n) = A198387(n).
A198436(n) = a(A198409(n)).
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MATHEMATICA
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wmax = 1000;
triples[w_] := Reap[Module[{u, v}, For[u = 1, u < w, u++, If[IntegerQ[v = Sqrt[(u^2 + w^2)/2]], Sow[{u^2, v^2, w^2}]]]]][[2]];
Flatten[DeleteCases[triples /@ Range[wmax], {}], 2][[All, 2]] (* Jean-François Alcover, Oct 19 2021 *)
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PROG
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(Haskell)
a198385 n = a198385_list !! (n-1)
a198385_list = map (^ 2) a198389_list
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CROSSREFS
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Sequence in context: A237202 A353152 A335717 * A134422 A016850 A309779
Adjacent sequences: A198382 A198383 A198384 * A198386 A198387 A198388
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller, Oct 24 2011
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STATUS
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approved
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