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A333868
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The number of ways to write n as the difference of two k-simplex numbers for k >= 2.
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3
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1, 3, 3, 4, 5, 4, 3, 6, 7, 4, 4, 4, 5, 9, 4, 4, 5, 5, 7, 9, 4, 4, 4, 6, 4, 7, 7, 4, 7, 5, 3, 6, 6, 11, 9, 4, 4, 6, 4, 4, 6, 4, 5, 11, 5, 4, 4, 6, 6, 6, 5, 4, 7, 12, 8, 6, 4, 4, 6, 4, 4, 8, 5, 8, 9, 4, 4, 7, 8, 4, 5, 4, 5, 8, 4, 8, 9, 4, 5, 8, 4, 6, 10, 7, 4, 6
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OFFSET
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2,2
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COMMENTS
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Records occur at indices 2, 3, 5, 6, 9, 10, 15, 35, 55, 105, 210, 1365, 2925, 3003,...
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LINKS
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EXAMPLE
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The a(9) = 6 ways to write 9 as the difference of k-simplex numbers for k > 2 are:
C(5, 2) - C(2, 2) = 10 - 1,
C(6, 2) - C(4, 2) = 15 - 6,
C(10, 2) - C(9, 2) = 45 - 36,
C(5, 3) - C(3, 3) = 10 - 1,
C(9, 8) - C(7, 8) = 9 - 0, and
C(10, 9) - C(9, 9) = 10 - 1,
where C(n,k) = binomial(n,k) = A007318(n,k).
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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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