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A234813
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Number of distinct integers of the form i+(i+1)+(i+2)+...+j, for 1 <= i <= j <= n.
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3
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1, 3, 5, 9, 12, 16, 21, 27, 33, 40, 47, 55, 63, 70, 77, 89, 101, 110, 123, 134, 146, 159, 171, 186, 200, 214, 229, 245, 260, 275, 293, 312, 329, 349, 369, 388, 411, 432, 451, 474, 496, 519, 542, 564, 586, 611, 635, 660, 689, 713
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OFFSET
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1,2
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COMMENTS
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See also A001227 = number of ways to write n as difference of triangular numbers. - M. F. Hasler, Apr 20 2014
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LINKS
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EXAMPLE
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a(3) = 5 because the possible integers are 1,2,3=1+2,5=2+3,6=1+2+3.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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