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A198438 Common differences in triples of squares in arithmetic progression, that are not a multiples of other triples in (A198384, A198385, A198386). 6
24, 120, 240, 336, 840, 840, 720, 1320, 2520, 2016, 3696, 2184, 5280, 5544, 6240, 3960, 3360, 9360, 10920, 10296, 4896, 6864, 14280, 18480, 6840, 22440, 17160, 10920, 20064, 28560, 9240, 31824, 31920, 31416, 26520, 16320, 12144, 41496, 47880, 43680, 50160 (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) = A198387(A198409(n)) = A198436(n) - A198435(n) = A198437(n) - A198436(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];

#[[2]] - #[[1]]& /@ DeleteCases[tt, t_List /; GCD@@t > 1 && MemberQ[tt, t/GCD@@t]] (* Jean-Fran├žois Alcover, Oct 22 2021 *)

PROG

(Haskell)

a198438 n = a198438_list !! (n-1)

a198438_list = map a198387 a198409_list

CROSSREFS

Sequence in context: A211465 A293893 A137799 * A256629 A114200 A229567

Adjacent sequences:  A198435 A198436 A198437 * A198439 A198440 A198441

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Oct 25 2011

STATUS

approved

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Last modified May 22 19:55 EDT 2022. Contains 353957 sequences. (Running on oeis4.)