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A075814
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Palindromic odd numbers with exactly 3 prime factors (counted with multiplicity).
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2
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99, 171, 333, 343, 363, 555, 575, 595, 747, 777, 909, 969, 1001, 1221, 1331, 1551, 1771, 3333, 3553, 5335, 5555, 5665, 5885, 5995, 7337, 7557, 7667, 7777, 7887, 9339, 9559, 9669, 9779, 9889, 11211, 11511, 11711, 11811, 12121, 12221, 12621, 12921
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OFFSET
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1,1
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LINKS
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EXAMPLE
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99=3^2*11, 171=3^2*19 and 333=3^2*37 are palindromic, odd and have exactly 3 prime factors.
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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[bigomega](n)=3; end; a := []; for n from 1 to 13000 by 2 do if test(n) then a := [op(a), n]; end; od; a;
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MATHEMATICA
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Select[Range[1, 13001, 2], PalindromeQ[#]&&PrimeOmega[#]==3&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Sep 05 2017 *)075814:"
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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