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A262619
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Number of parts in the symmetric representation of sigma(n) in two successive octants of two quadrants.
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3
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1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 3, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 3, 1, 1, 1, 1, 1, 3, 1, 1, 1, 3, 3, 3, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1, 5, 1, 3, 1, 1, 1, 3, 3, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 5, 1, 1, 1, 3, 1, 3, 1, 1, 1, 3, 1, 3, 1, 3, 1, 1, 3, 5, 1, 1, 1, 1, 1, 3, 1
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OFFSET
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1,9
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COMMENTS
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In the diagram of the top view of the pyramid described in A244050 consider a 90-degree sector on two successive octants of two quadrants. The area of the top triangle is equal to 1 and the sum of the areas of all parts (or regions) added at n-th stage equals sigma(n), the sum of the divisors of n.
a(n) is also the number of terraces at n-th level (starting from the top) in the mentioned sector of the pyramid.
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LINKS
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FORMULA
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CROSSREFS
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Cf. A000203, A196020, A235791, A236104, A237270, A237271, A237591, A237593, A244050, A244971, A245092, A262618.
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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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