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Search: id:A112886
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| A112886 |
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Triangle-free positive integers. |
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+0
9
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| 1, 2, 4, 5, 7, 8, 11, 13, 14, 16, 17, 19, 22, 23, 25, 26, 29, 31, 32, 34, 35, 37, 38, 41, 43, 44, 46, 47, 49, 52, 53, 58, 59, 61, 62, 64, 65, 67, 68, 71, 73, 74, 76, 77, 79, 82, 83, 85, 86, 88, 89, 92, 94, 95, 97, 98, 101, 103, 104, 106, 107, 109, 113, 115, 116, 118, 119
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Those positive integers not in A113502.
a(n) = A132895(n)/2. - Ray Chandler (rayjchandler(AT)sbcglobal.net), May 29 2008
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LINKS
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Leroy Quet, Home Page (listed in lieu of email address)
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EXAMPLE
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14 is included because the divisors of 14 are 1, 2, 7 and 14, none of which are triangular numbers > 1.
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MATHEMATICA
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v={}; Do[If[b=Select[Divisors[n], #>1 && IntegerQ[(1+8#)^(1/2)]&]; b=={}, AppendTo[v, n]], {n, 138}]; v (Firoozbakht)
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CROSSREFS
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Cf. A113502, A000217, A005117.
Sequence in context: A085370 A006693 A158850 this_sequence A111040 A147807 A022559
Adjacent sequences: A112883 A112884 A112885 this_sequence A112887 A112888 A112889
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet Jan 10 2006
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EXTENSIONS
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More terms from Farideh Firoozbakht (mymontain(AT)yahoo.com), Jan 12 2006
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