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Search: id:A063163
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| A063163 |
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Composite numbers which in base 7 contain their largest proper factor as a substring. |
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+0 1
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| 49, 77, 91, 119, 133, 161, 203, 217, 259, 287, 301, 329, 343, 371, 413, 427, 469, 497, 511, 539, 551, 553, 581, 623, 637, 679, 707, 721, 749, 763, 791, 833, 847, 889, 917, 931, 959, 973, 989, 1001, 1043, 1057, 1099, 1127, 1141, 1169, 1183, 1211, 1253
(list; graph; listen)
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OFFSET
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1,1
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MATHEMATICA
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Do[ If[ !PrimeQ[ n ] && StringPosition[ ToString[ FromDigits[ IntegerDigits[ n, 7 ] ] ], ToString[ FromDigits[ IntegerDigits[ Divisors[ n ] [ [ -2 ] ], 7 ] ] ] ] != {}, Print[ n ] ], {n, 2, 2000} ]
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CROSSREFS
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Cf. A062238.
Sequence in context: A112074 A112057 A038510 this_sequence A103216 A036307 A056938
Adjacent sequences: A063160 A063161 A063162 this_sequence A063164 A063165 A063166
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KEYWORD
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base,nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 08 2001
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