This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A192138 #9 Aug 06 2024 02:06:50 %S A192138 2,3,2,5,7,2,3,11,2,5,3,2,313,7,2,323,3,101,313,717,11,5,2,343,131, %T A192138 151,353,181,191,323,373,3,383,2,737,313,747,3113,7,313,353,373,383, %U A192138 343,1331,31113,767,353,313,2,323,5,373,3223,797,727,3,383,757,787,3553 %N A192138 Palindromic concatenation of prime divisors of numbers from A192137. %e A192138 a(13) = 313 because A192137(13) = 39 = 3 * 13. %t A192138 f[n_] := FromDigits[Flatten[IntegerDigits /@ FactorInteger[n][[;; , 1]]]]; Select[f /@ Range[2, 1900], PalindromeQ] (* _Amiram Eldar_, Aug 06 2024 *) %Y A192138 Cf. A002113, A002385, A084317, A084092, A192137, A192139, A192140, A192141. %K A192138 nonn,base %O A192138 1,1 %A A192138 _Jaroslav Krizek_, Jun 24 2011 %E A192138 More terms from _Amiram Eldar_, Aug 06 2024