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A038481
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Sums of 2 distinct powers of 7.
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4
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8, 50, 56, 344, 350, 392, 2402, 2408, 2450, 2744, 16808, 16814, 16856, 17150, 19208, 117650, 117656, 117698, 117992, 120050, 134456, 823544, 823550, 823592, 823886, 825944, 840350, 941192, 5764802, 5764808, 5764850, 5765144, 5767202
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OFFSET
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0,1
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LINKS
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FORMULA
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G.f.: ((1-x)*(1-7*x))^(-1) * (2 - 8*x + sum_{k>=0} ((1+5*7^k)*x^(k*(k+1)/2) + (1+41*7^k)*x^(1+k*(k+1)/2))). - Robert Israel, Feb 09 2018
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MAPLE
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seq(seq(7^i+7^j, j=0..i-1), i=1..10); # Robert Israel, Feb 09 2018
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MATHEMATICA
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Sort[Total/@Subsets[7^Range[0, 10], {2}]] (* Harvey P. Dale, Jul 29 2015 *)
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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