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Search: id:A161732
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| A161732 |
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Fixed points of the TITO operation (A161594) that are also composite palindromes. |
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+0
2
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| 4, 6, 8, 9, 22, 33, 44, 55, 66, 77, 88, 99, 121, 202, 242, 252, 262, 303, 343, 363, 393, 404, 484, 505, 525, 606, 616, 626, 686, 707, 808, 909, 939, 1111, 1331, 1441, 1661, 1991, 2112, 2222, 2662, 2772, 2882, 3333, 3443, 3773, 3883, 3993, 4224, 4444, 5445
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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This sequence is a proper superset of A046351 (palindromic composite numbers with only palindromic prime factors). The smallest number that doesn't belong to A046351 is 72927. The numbers that are in this sequence and are not in A046351 are given in A161730.
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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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MATHEMATICA
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reversepower[{n_, k_}] := FromDigits[Reverse[IntegerDigits[n]]]^k f[n_] := FromDigits[ Reverse[IntegerDigits[Times @@ Map[reversepower, FactorInteger[n]]]]] rev[n_] := FromDigits[Reverse[IntegerDigits[n]]] Select[Range[10000], f[ # ] == # && rev[ # ] == # && ! PrimeQ[ # ] &]
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CROSSREFS
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Cf. A161594, A161597, A161598, A161600, A046351
Sequence in context: A032350 A078337 A046351 this_sequence A066307 A158340 A099071
Adjacent sequences: A161729 A161730 A161731 this_sequence A161733 A161734 A161735
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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 17 2009
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EXTENSIONS
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Edited by N. J. A. Sloane, Jun 23 2009
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