A075811 Palindromic even squarefree numbers with an even number of distinct prime factors.

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

Links

Table of n, a(n) for n=1..38.

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

Adjacent sequences: A075808 A075809 A075810 * A075812 A075813 A075814

Keyword

nonn,base

Author

Jani Melik, Oct 13 2002

Extensions

Edited by Dean Hickerson, Oct 21 2002

Status

approved