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Search: id:A161957
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| 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 27, 29, 31, 37, 41, 43, 45, 47, 51, 53, 59, 61, 63, 67, 71, 73, 79, 83, 85, 89, 93, 95, 97, 101, 103, 107, 109, 111, 113, 119, 123, 127, 131, 137, 139, 149, 151, 153, 157, 163, 167, 173, 179, 181, 187, 189, 191, 193, 197, 199
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Fixed points of the TITO2 operation (the TITO operation in binary): numbers a(n) such that A161955(a(n)) = a(n).
All numbers in the sequence are odd. All odd primes A065091 belong to the sequence.
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LINKS
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T. Khovanova, Turning Numbers Inside Out [From Tanya Khovanova (tanyakh(AT)yahoo.com), Jul 07 2009]
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EXAMPLE
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95 is in this sequence because 95 = 5*19. Prime factors in binary are: 101 and 10011.
Reversing them we get 101 and 11001. The product of the last two numbers is 1111101, which is
the reverse of the binary representation of 95 (1011111).
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MATHEMATICA
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reverseBinPower[{n_, k_}] := FromDigits[Reverse[IntegerDigits[n, 2]], 2]^k fBin[n_] := FromDigits[ Reverse[IntegerDigits[ Times @@ Map[reverseBinPower, FactorInteger[n]], 2]], 2] Select[Range[300], fBin[ # ] == # &]
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CROSSREFS
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Cf. A161955, A161594, A161597.
Sequence in context: A033041 A077797 A033039 this_sequence A082720 A033037 A158333
Adjacent sequences: A161954 A161955 A161956 this_sequence A161958 A161959 A161960
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KEYWORD
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base,nonn
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AUTHOR
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Tanya Khovanova (tanyakh(AT)yahoo.com), Jun 22 2009
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EXTENSIONS
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Comments condensed by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 14 2009
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