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A226732 Palindromes that cannot be expressed as a nontrivial product of two palindromes. 2

%I #12 Feb 21 2020 09:59:17

%S 1,2,3,5,7,11,101,111,131,141,151,161,171,181,191,212,232,252,272,292,

%T 313,323,343,353,373,383,414,434,454,474,494,515,525,535,545,565,575,

%U 585,595,656,676,717,727,737,747,757,767,787,797,818,838,858,878,898

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

%C Complement of A078337.

%H Giovanni Resta, <a href="/A226732/b226732.txt">Table of n, a(n) for n = 1..10000</a>

%t 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}]]]]]

%Y Cf. A078337.

%K nonn,base

%O 1,2

%A _Jayanta Basu_, Jun 16 2013

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Last modified April 25 04:42 EDT 2024. Contains 371964 sequences. (Running on oeis4.)