A192219 Numbers m such that set of divisors of m is equal to set of reversals of divisors of m but all divisors of m are not palindromic.

1226221, 13488431, 123848321, 12467976421, 1030507050301, 1120237320211, 1225559555221, 1234469644321, 1334459544331, 11335577553311, 100330272033001, 101222252222101, 103023070320301, 113143969341311, 121363494363121, 134312696213431

Offset

1,1

Comments

All terms are palindromic (subsequence of A002113 - palindromic numbers).

Subsequence of A188650 (numbers that are divisible by all reversals of their divisors).

Union a(n) and A062687 (numbers all of whose divisors are palindromic) is sequence of numbers m such that set of divisors of m is equal to set of reversals of divisors of m: {1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 44, 55, 66, 77, 88, 99, 101, 121, 131, ..., 1226221, ...). - Jaroslav Krizek, Jul 18 2011.

Links

Table of n, a(n) for n=1..16.

Example

1226221 has divisors 1, 1021, 1201, 1226221. Set of divisors is equal to set of reversals of divisors. Divisors 1021 and 1201 are not palindromic.

Mathematica

t = Union[Flatten[Table[d = IntegerDigits[n]; {FromDigits[Join[d, Reverse[d]]], FromDigits[Join[d, Reverse[Most[d]]]]}, {n, 0, 99999}]]]; okQ[n_] := Module[{f = Divisors[n], r}, r = f; Do[r[[i]] = FromDigits[Reverse[IntegerDigits[f[[i]]]]], {i, Length[f]}];  f == Sort[r] && f != r]; Select[t, okQ] (* T. D. Noe, Jul 14 2011 *)

Crossrefs

Sequence in context: A257159 A254741 A203259 * A282424 A129347 A071146

Adjacent sequences: A192216 A192217 A192218 * A192220 A192221 A192222

Keyword

nonn,base

Author

Jaroslav Krizek, Jul 13 2011

Extensions

a(5)-a(16) (including six found by T. D. Noe) from Donovan Johnson, Jul 14 2011

Status

approved