A084349 - OEIS

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A084349

Squarefree numbers which can not be written as sum of two squares.

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; internal format)

	OFFSET	`1,2`
	LINKS	`Reinhard Zumkeller, Table of n, a(n) for n = 1..10000` `Index entries for sequences related to sums of squares`
	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.`
	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. A020893, A005117, A000290, A010052.` `Sequence in context: A076644 A189626 A087642 * A126003 A047556 A015819` `Adjacent sequences: A084346 A084347 A084348 * A084350 A084351 A084352`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jun 21 2003`

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Last modified February 17 19:13 EST 2012. Contains 206085 sequences.