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 A050700 #13 Oct 18 2018 09:45:52 %S A050700 15,26,39,49,58,115,117,122,123,126,129,143,147,155,158,159,165,169, %T A050700 177,178,183,185,187,203,205,225,226,244,246,265,285,286,289,294,314, %U A050700 315,319,326,327,329,335,338,339,355,366,369,394,398,406,415,418,425 %N A050700 Composite numbers n smaller than their decimal reverse but having the same number of prime factors. %H A050700 Charles R Greathouse IV, <a href="/A050700/b050700.txt">Table of n, a(n) for n = 1..10000</a> %e A050700 a(n)=143 -> a(n)-reversed=341 gives pair (143,341) of which only the smaller value 143 is in this sequence. %t A050700 rev[n_]:=FromDigits[Reverse[IntegerDigits[n]]]; Select[Range[425],!PrimeQ[#]&&PrimeOmega[#]==PrimeOmega[x=rev[#]]&&#<x&] (* _Jayanta Basu_, May 31 2013 *) %o A050700 (PARI) is(n)=my(r=fromdigits(Vecrev(digits(n)))); n<r && !isprime(n) && !isprime(r) && bigomega(n)==bigomega(r) \\ _Charles R Greathouse IV_, Oct 17 2018 %Y A050700 Cf. A050699, A050701. %K A050700 nonn,base %O A050700 1,1 %A A050700 _Patrick De Geest_, Aug 15 1999 %E A050700 Name edited and offset corrected by _Charles R Greathouse IV_, Oct 17 2018