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A198436 Second term of a triple of squares in arithmetic progression, which is not a multiple of another triple in (A198384, A198385, A198386). 7
25, 169, 289, 625, 841, 1369, 1681, 3721, 2809, 4225, 4225, 7225, 5329, 7225, 7921, 10201, 12769, 9409, 11881, 15625, 21025, 21025, 22201, 18769, 32761, 24649, 29929, 38809, 34225, 28561, 48841, 34225, 37249, 42025, 52441, 66049, 70225, 42025, 48841, 54289 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Ray Chandler, Table of n, a(n) for n = 1..10000

Keith Conrad, Arithmetic progressions of three squares

Reinhard Zumkeller, Table of initial values

FORMULA

a(n) = A198440(n)^2 = A198385(A198409(n)).

a(n) - A198435(n) = A198437(n) - a(n) = A198438(n).

MATHEMATICA

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]];

tt = Flatten[DeleteCases[triples /@ Range[wmax], {}], 2];

DeleteCases[tt, t_List /; GCD @@ t>1 && MemberQ[tt, t/GCD @@ t]][[All, 2]] (* Jean-Fran├žois Alcover, Oct 20 2021 *)

PROG

(Haskell)

a198436 n = a198436_list !! (n-1)

a198436_list = map a198385 a198409_list

CROSSREFS

Cf. A198385, A198409, A198435, A198437, A198438, A198440.

Sequence in context: A255419 A324899 A338892 * A080109 A017126 A007204

Adjacent sequences:  A198433 A198434 A198435 * A198437 A198438 A198439

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Oct 25 2011

STATUS

approved

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Last modified July 3 23:09 EDT 2022. Contains 355058 sequences. (Running on oeis4.)