A340252 Numbers whose pairwise products of divisors are all palindromic.

1, 2, 3, 4, 5, 7, 11, 22, 33, 101, 121, 131, 151, 181, 191, 202, 303, 313, 353, 373, 383, 727, 757, 787, 797, 919, 929, 1111, 2222, 10201, 10301, 10501, 10601, 11311, 11411, 12221, 12421, 12721, 12821, 13331, 13831, 13931, 14341, 14741, 15451, 15551, 16061, 16361, 16561, 16661

Offset

1,2

Comments

Supersequence of A002385 (palindromic primes).

A subsequence of A062687 (numbers all of whose divisors are palindromic).

Links

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

Example

The pairwise products of the divisors of 22 (2,11,22,44,242) are all palindromic, so 22 is in the sequence.

Mathematica

fQ[n_]:=AllTrue[Union[Times@@@Subsets[Divisors[n], {2}]], PalindromeQ]; Select[Range[20000], fQ]

Crossrefs

Cf. A002385, A062687.

Sequence in context: A339357 A279065 A327325 * A324989 A015856 A174165

Adjacent sequences: A340249 A340250 A340251 * A340253 A340254 A340255

Keyword

base,easy,nonn

Author

Ivan N. Ianakiev, Jan 02 2021

Status

approved