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A242313
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Numbers belonging to a geometric sequence whose ratio is 2 and whose first term ends in 1.
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0
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1, 2, 4, 8, 11, 16, 21, 22, 31, 32, 41, 42, 44, 51, 61, 62, 64, 71, 81, 82, 84, 88, 91, 101, 102, 111, 121, 122, 124, 128, 131, 141, 142, 151, 161, 162, 164, 168, 171, 176, 181, 182, 191, 201, 202, 204, 211, 221, 222, 231, 241, 242, 244, 248, 251, 256, 261
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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EXAMPLE
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176 is in the sequence because it belongs to 11, 22, 44, 88, 176, with first term 11.
96, which belongs to 3, 6, 12, 24, 48, 96 with first term 3, is not a term.
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PROG
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(PARI) isok(n) = ((n/2^valuation(n, 2)) % 10) == 1; \\ Michel Marcus, May 14 2014
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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