A075800 Palindromic numbers which are products of an odd number of distinct primes.

2, 3, 5, 7, 11, 66, 101, 131, 151, 181, 191, 222, 282, 313, 353, 373, 383, 434, 474, 494, 555, 595, 606, 646, 727, 757, 777, 787, 797, 919, 929, 969, 1001, 1221, 1551, 1771, 2222, 2882, 3333, 3553, 4334, 4994, 5335, 5555, 5665, 5885, 5995, 6006, 6226, 6446, 6886

Offset

1,1

Links

Chai Wah Wu, Table of n, a(n) for n = 1..10000

Example

191 is palindromic and prime, 222=2*3*37 is palindromic and a product of 3 distinct primes.

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 1 to 7000 do if test(n) then a := [op(a), n]; end; od; a;

Mathematica

Select[Range[10000], PalindromeQ[#] && MoebiusMu[#] == -1 &] (* Paolo Xausa, Mar 10 2025 *)

Crossrefs

Cf. A002385, A069217, A032350, A030059, A075799, A075806 (first differences).

Sequence in context: A004089 A092791 A070892 * A067909 A323697 A103850

Adjacent sequences: A075797 A075798 A075799 * A075801 A075802 A075803

Keyword

nonn,base

Author

Jani Melik, Oct 13 2002

Extensions

Edited by Dean Hickerson, Oct 21 2002

Status

approved