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A025619
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Numbers of form 4^i*7^j, with i, j >= 0.
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5
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1, 4, 7, 16, 28, 49, 64, 112, 196, 256, 343, 448, 784, 1024, 1372, 1792, 2401, 3136, 4096, 5488, 7168, 9604, 12544, 16384, 16807, 21952, 28672, 38416, 50176, 65536, 67228, 87808, 114688, 117649, 153664, 200704, 262144, 268912, 351232, 458752, 470596
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OFFSET
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1,2
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LINKS
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FORMULA
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Sum_{n>=1} 1/a(n) = (4*7)/((4-1)*(7-1)) = 14/9. - Amiram Eldar, Sep 24 2020
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MATHEMATICA
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n=10^6; Flatten[Table[4^i*7^j, {i, 0, Log[4, n]}, {j, 0, Log[7, n/4^i]}]]//Sort (* Amiram Eldar, Sep 24 2020 *)
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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