A075814 Palindromic odd numbers with exactly 3 prime factors (counted with multiplicity).

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

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

99=3^2*11, 171=3^2*19 and 333=3^2*37 are palindromic, odd and have exactly 3 prime factors.

Maple

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;

Mathematica

Select[Range[1, 13001, 2], PalindromeQ[#]&&PrimeOmega[#]==3&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Sep 05 2017 *)075814:"

Crossrefs

Cf. A046316.

Sequence in context: A126230 A055164 A075815 * A320707 A235228 A157947

Adjacent sequences: A075811 A075812 A075813 * A075815 A075816 A075817

Keyword

nonn,base

Author

Jani Melik, Oct 13 2002

Extensions

Edited by Dean Hickerson, Oct 21 2002

Status

approved