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A198386
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Third of a triple of squares in arithmetic progression.
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13
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49, 196, 289, 441, 529, 784, 961, 1156, 1225, 1681, 1764, 2116, 2209, 2401, 2401, 2601, 3136, 3844, 3969, 4624, 4761, 4900, 5041, 5329, 5929, 6241, 6724, 7056, 7225, 7921, 8281, 8464, 8649, 8836, 9409, 9604, 9604, 10404, 10609, 11025, 12544, 12769, 13225
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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) = A198390(n)^2.
a(n) - A198385(n) = A198385(n) - A198384(n) = A198387(n).
A198437(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, 3]] (* Jean-François Alcover, Oct 19 2021 *)
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PROG
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(Haskell)
a198386 n = a198386_list !! (n-1)
a198386_list = map (^ 2) a198390_list
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CROSSREFS
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Sequence in context: A244184 A251214 A158638 * A351663 A016982 A157919
Adjacent sequences: A198383 A198384 A198385 * A198387 A198388 A198389
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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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