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A118629
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Number of n-digit integers with decimal digits in increasing order.
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1
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OFFSET
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1,1
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COMMENTS
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There are precisely 512 such numbers, see A009993.
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LINKS
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FORMULA
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a(1)=1, at n>1: a(n)=binomial(10, n)(1 - n/10)
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EXAMPLE
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a(2)=36 because there are 36 two-digit integers whose decimal digits are in increasing order (see A009993): 12, 13, 14, 15, 16, 17, 18, 19, 23, 24, 25, 26, 27, 28, 29, 34, 35, 36, 37, 38, 39, 45, 46, 47, 48, 49, 56, 57, 58, 59, 67, 68, 69, 78, 79, 89
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CROSSREFS
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KEYWORD
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fini,full,nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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