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 A087305 #11 May 19 2024 02:11:28
%S A087305 13,107,1002,10002,100006,1000007,10000013,100000005,1000000007,
%T A087305 10000000006,100000000007,1000000000006,10000000000003,
%U A087305 100000000000002,1000000000000003,10000000000000002,100000000000000005,1000000000000000005,10000000000000000021,100000000000000000031
%N A087305 Smallest n-digit non-palindromic number such that it and its digit reversal have the same prime signature.
%e A087305 a(6) = 100006 = 2*13*1613 and 600001 = 19*23*1373 both have prime signature p*q*r, p,q,r are primes.
%o A087305 (PARI) rev(n) = fromdigits(Vecrev(digits(n)));
%o A087305 psig(n) = vecsort(factor(n)[,2]~);
%o A087305 a(n) = {my(k = 10^n+1); while(k == rev(k) || psig(k) != psig(rev(k)), k++); k;} \\ _Amiram Eldar_, May 19 2024
%Y A087305 Cf. A085869, A068893.
%K A087305 base,nonn
%O A087305 2,1
%A A087305 _Amarnath Murthy_, Sep 02 2003
%E A087305 More terms from _David Wasserman_, Apr 19 2005
%E A087305 More terms from _Amiram Eldar_, May 19 2024