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Search: id:A131323
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| A131323 |
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Odd numbers n such that the binary expansion of n ends in an even number of 1's. |
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+0
2
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| 3, 11, 15, 19, 27, 35, 43, 47, 51, 59, 63, 67, 75, 79, 83, 91, 99, 107, 111, 115, 123, 131, 139, 143, 147, 155, 163, 171, 175, 179, 187, 191, 195, 203, 207, 211, 219, 227, 235, 239, 243, 251, 255, 259, 267, 271, 275, 283, 291, 299, 303, 307, 315, 319, 323, 331
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Also numbers of the form (4^a)*b - 1 with positive integer a and odd integer b. The sequence has linear growth and the limit of a(n)/n is 6. - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 18 2007
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EXAMPLE
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11 in binary is 1011, which ends with two 1's.
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MATHEMATICA
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Select[Range[500], OddQ[ # ] && EvenQ[FactorInteger[ # + 1][[1, 2]]] &] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 18 2007
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CROSSREFS
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Cf. A121539.
Adjacent sequences: A131320 A131321 A131322 this_sequence A131324 A131325 A131326
Sequence in context: A044971 A106374 A075330 this_sequence A050592 A032466 A060698
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KEYWORD
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nonn,easy
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AUTHOR
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Nadia Heninger (nadiah(AT)cs.princeton.edu) and njas, Dec 16 2007
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EXTENSIONS
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More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 18 2007
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