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Search: id:A128826
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| A128826 |
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a(n) = 10^(2n-1) minus largest square less than 10^(2n-1). |
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+0
1
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| 1, 39, 144, 1756, 49116, 484471, 4175271, 38053824, 10649244, 1064924400, 43246886799, 529955487744, 2399106211776, 50173961567511, 590207432515431, 2099745368512359, 20237877241133151, 126421128012287511
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OFFSET
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1,2
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COMMENT
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For even indices a(2k) = 2*10^k-1, hence only odd powers of 10 are considered in this sequence.
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FORMULA
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a(n)=10^(2n-1)-A061433(2n-1)
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EXAMPLE
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a(1)=1 because 10 - 3^2 = 1, a(2)=39 because 1000-31^2 = 39, a(2)=144 because 100000-316^2 = 144.
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MATHEMATICA
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Table[10^n-Floor[(10^n-1)^(1/2)]^2, {n, 1, 40, 2}]
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CROSSREFS
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Cf. A061433.
Adjacent sequences: A128823 A128824 A128825 this_sequence A128827 A128828 A128829
Sequence in context: A044371 A044752 A072253 this_sequence A105838 A124619 A068975
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KEYWORD
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nonn
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AUTHOR
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Zak Seidov (zakseidov(AT)gmail.com), Apr 12 2007
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