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Search: id:A075808
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| A075808 |
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Palindromic odd composite numbers with an odd number of distinct prime factors. |
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+0
1
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| 555, 595, 777, 969, 1001, 1221, 1551, 1771, 3333, 3553, 5335, 5555, 5665, 5885, 5995, 7337, 7557, 7667, 7777, 7887, 9339, 9669, 9779, 9889, 11211, 11811, 12121, 12621, 12921, 13731, 14241, 14541, 15051, 15951, 16261, 16761, 17171, 18381
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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555=3*5*37, 595=5*7*17 and 777=3*7*37 are palindromic, odd, composite and products of an odd number of distinct primes.
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MAPLE
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test := proc(n) local d; d := convert(n, base, 10); return ListTools[Reverse](d)=d and numtheory[mobius](n)=-1 and not isprime(n); end; a := []; for n from 1 to 30000 by 2 do if test(n) then a := [op(a), n]; end; od; a;
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CROSSREFS
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Cf. A046389.
Sequence in context: A035849 A028686 A045046 this_sequence A043511 A104809 A105979
Adjacent sequences: A075805 A075806 A075807 this_sequence A075809 A075810 A075811
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KEYWORD
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nonn,base
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AUTHOR
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Jani Melik (jani_melik(AT)hotmail.com), Oct 13 2002
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EXTENSIONS
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Edited by Dean Hickerson (dean.hickerson(AT)yahoo.com), Oct 21 2002
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