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 A198409 Positions in sequences A198384, A198385 and A198386 to indicate triples of squares in arithmetic progression, that are not multiples of earlier triples. 15
 1, 3, 5, 7, 10, 13, 15, 23, 24, 26, 30, 35, 39, 42, 45, 47, 51, 54, 62, 69, 70, 72, 83, 84, 88, 97, 98, 102, 107, 114, 115, 124, 126, 129, 136, 141, 142, 143, 156, 157, 167, 169, 172, 177, 181, 188, 191, 201, 205, 208, 214, 218, 229, 230, 237, 244, 249, 253 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS A198435(n) = A198384(a(n)); A198439(n) = A198388(a(n)); A198436(n) = A198385(a(n)); A198440(n) = A198389(a(n)); A198437(n) = A198386(a(n)); A198441(n) = A198390(a(n)); A198438(n) = A198387(a(n)). LINKS Ray Chandler, Table of n, a(n) for n = 1..10000 Reinhard Zumkeller, Table of initial values FORMULA A008966(A050873(A198439(n),A050873(A198440(n),A050873(A198441(n))))) = 1. 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]; Position[tt, t_List /; SquareFreeQ[GCD@@t]] // Flatten (* Jean-François Alcover, Oct 24 2021 *) PROG (Haskell) import Data.List (elemIndices) a198409 n = a198409_list !! (n-1) a198409_list = map (+ 1) \$ elemIndices 1 \$ map a008966 \$ zipWith gcd a198384_list \$ zipWith gcd a198385_list a198386_list CROSSREFS Sequence in context: A050090 A152004 A298862 * A330072 A213510 A130257 Adjacent sequences: A198406 A198407 A198408 * A198410 A198411 A198412 KEYWORD nonn AUTHOR Reinhard Zumkeller, Oct 25 2011 STATUS approved

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Last modified July 18 13:57 EDT 2024. Contains 374378 sequences. (Running on oeis4.)