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A049983
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a(n) is the number of arithmetic progressions of 2 or more positive integers, strictly increasing with sum <= n.
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19
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0, 0, 1, 2, 4, 7, 10, 13, 19, 24, 29, 37, 43, 50, 62, 70, 78, 92, 101, 112, 129, 141, 152, 171, 185, 199, 221, 237, 251, 278, 293, 310, 337, 356, 377, 409, 427, 448, 480, 505, 525, 563, 584, 609, 651, 677, 700, 742, 768, 800, 843, 873, 899, 948, 981, 1014, 1062, 1095, 1124, 1183, 1213, 1248, 1304, 1341, 1380
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OFFSET
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1,4
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LINKS
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FORMULA
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G.f.: (g.f. of A049982)/(1-x). (End)
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EXAMPLE
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a(7) = 10 because we have the following arithmetic progressions of two or more positive integers, strictly increasing with sum <= n = 7: 1+2, 1+3, 1+4, 1+5, 1+6, 2+3, 2+4, 2+5, 3+4, and 1+2+3. - Petros Hadjicostas, Sep 27 2019
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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