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 A084349 Squarefree numbers that are not the sum of two squares. 2
 1, 3, 6, 7, 11, 14, 15, 19, 21, 22, 23, 30, 31, 33, 35, 38, 39, 42, 43, 46, 47, 51, 55, 57, 59, 62, 66, 67, 69, 70, 71, 77, 78, 79, 83, 86, 87, 91, 93, 94, 95, 102, 103, 105, 107, 110, 111, 114, 115, 118, 119, 123, 127, 129, 131, 133, 134, 138, 139, 141, 142, 143 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Intersection of A005117 (squarefree) and A018825. - Michel Marcus, Dec 02 2015 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 EXAMPLE A005117(10) = 14: 14 - 1^2 = 13, 14 - 2^2 = 10 and 14 - 3^3 = 5 are nonsquares, therefore 14 is a term; A005117(9) = 13 is not a term: A020893(4) = 13 = 2^2 + 3^2. MATHEMATICA Prepend[Select[Range@ 144, SquareFreeQ@ # && SquaresR[2, #] == 0 &], 1] (* Michael De Vlieger, Dec 02 2015 *) PROG (Haskell) a084349 n = a084349_list !! (n-1) a084349_list = 1 : filter (\x -> all (== 0) \$ map (a010052 . (x -)) \$                            takeWhile (<= x) a000290_list) a005117_list -- Reinhard Zumkeller, Dec 11 2011 CROSSREFS Cf. A000290, A005117, A010052, A018825, A020893. Sequence in context: A189626 A297292 A087642 * A126003 A047556 A255053 Adjacent sequences:  A084346 A084347 A084348 * A084350 A084351 A084352 KEYWORD nonn AUTHOR Reinhard Zumkeller, Jun 21 2003 STATUS approved

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Last modified May 19 13:18 EDT 2019. Contains 323393 sequences. (Running on oeis4.)