A226732 Palindromes that cannot be expressed as a nontrivial product of two palindromes.

1, 2, 3, 5, 7, 11, 101, 111, 131, 141, 151, 161, 171, 181, 191, 212, 232, 252, 272, 292, 313, 323, 343, 353, 373, 383, 414, 434, 454, 474, 494, 515, 525, 535, 545, 565, 575, 585, 595, 656, 676, 717, 727, 737, 747, 757, 767, 787, 797, 818, 838, 858, 878, 898

Offset: 1

Author

Jayanta Basu, Jun 16 2013

Keywords

• nonn
• base

Comments

Complement of A078337.

Links

• Giovanni Resta, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A078337.

Programs

Mathematica

palQ[n_] := Reverse[x = IntegerDigits[n]] == x; t1 = Rest[Select[Range[900], palQ[#] &]]; Join[{1}, Complement[t1, Union[Flatten[Table[i*j, {i, t1}, {j, t1}]]]]]