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Search: id:A144096
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| A144096 |
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A positive integer n is included if at least one of the exponents of the prime-factorization of n does not occur anywhere in n when the exponents and n are represented in base 2. |
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+0
2
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| 8, 32, 40, 63, 64, 72, 96, 128, 136, 168, 224, 243, 264, 288, 296, 297, 320, 328, 384, 480, 486, 512, 513, 520, 544, 552, 576, 584, 594, 608, 640, 648, 680, 800, 891, 972, 992, 1024, 1026, 1029, 1032, 1056, 1064, 1088, 1096, 1120, 1152, 1160, 1161, 1188
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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A144095(n) = A001221(n) if n is not included in this sequence.
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LINKS
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Leroy Quet, Home Page (listed in lieu of email address)
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EXAMPLE
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40 has the prime-factorization 2^3 * 5^1. So the exponents are 3 and 1. 40 in binary is 101000. 3 = 11 in binary. 11 does not occur anywhere in 101000. 1 is 1 in binary. 1 does occur (twice) in 101000. Since at least one exponent (3 = 11 in binary) does not occur in 101000 (= 40 in decimal), then 40 is in the sequence.
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MAPLE
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isA144096 := proc(n) local n2, a, ifa, e2, p ; n2 := convert(n, base, 2) ; ifa := ifactors(n)[2] ; for p in ifa do e2 := convert( op(2, p), base, 2) ; if not verify(n2, e2, 'superlist') then RETURN(true) ; fi; od: RETURN(false) ; end: for n from 1 to 2000 do if isA144096(n) then printf("%d, ", n) ; fi; od: [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 17 2008]
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CROSSREFS
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A144095
Sequence in context: A102275 A115948 A059880 this_sequence A127988 A129749 A005879
Adjacent sequences: A144093 A144094 A144095 this_sequence A144097 A144098 A144099
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KEYWORD
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base,nonn
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AUTHOR
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Leroy Quet Sep 10 2008
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EXTENSIONS
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63 and 64 inserted and extended by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 17 2008
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