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A075811
Palindromic even squarefree numbers with an even number of distinct prime factors.
0
6, 22, 202, 262, 454, 626, 818, 838, 858, 878, 898, 2002, 2442, 4774, 6666, 20302, 20602, 22322, 22422, 22522, 22622, 22722, 22822, 24142, 24242, 24842, 26562, 26662, 26762, 26962, 28482, 28682, 41014, 41314, 41414, 41614, 41714, 43034
OFFSET
1,1
EXAMPLE
22=2*11 and 858=2*3*11*13 are palindromic, even, squarefree and have an even number of prime factors.
MAPLE
test := proc(n) local d; d := convert(n, base, 10); return ListTools[Reverse](d)=d and numtheory[mobius](n)=1; end; a := []; for n from 2 to 44000 by 2 do if test(n) then a := [op(a), n]; end; od; a;
MATHEMATICA
Select[Range[2, 44000, 2], MoebiusMu[ # ]==1&&IntegerDigits[ # ]==Reverse[IntegerDigits[ # ]]&]
Select[Range[2, 44000, 2], SquareFreeQ[#]&&EvenQ[PrimeNu[#]]&& # == IntegerReverse[ #]&] (* The program uses the IntegerReverse function from Mathematica version 10 *) (* Harvey P. Dale, Mar 31 2016 *)
CROSSREFS
Sequence in context: A090372 A009366 A230964 * A302926 A121796 A051224
KEYWORD
nonn,base
AUTHOR
Jani Melik, Oct 13 2002
EXTENSIONS
Edited by Dean Hickerson, Oct 21 2002
STATUS
approved