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 A046350 #17 Apr 07 2021 02:30:14 %S A046350 9,15,21,25,27,33,35,45,49,55,63,75,77,81,99,105,121,125,135,147,165, %T A046350 175,189,225,231,243,245,275,297,303,315,343,363,375,385,393,405,441, %U A046350 453,495,505,525,539,543,567,573,605,625,655,675,693,707,729,735,755 %N A046350 Odd composite numbers with only palindromic prime factors. %H A046350 Harvey P. Dale, <a href="/A046350/b046350.txt">Table of n, a(n) for n = 1..1000</a> %t A046350 palQ[n_]:=Reverse[x=IntegerDigits[n]]==x; Select[Range[9,755,2],!PrimeQ[#]&&And@@palQ/@First/@FactorInteger[#]&] (* _Jayanta Basu_, Jun 05 2013 *) %t A046350 Select[Range[9,800,2],CompositeQ[#]&&AllTrue[FactorInteger[#][[All,1]], PalindromeQ]&] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Mar 08 2018 *) %o A046350 (Python) %o A046350 from sympy import isprime, primefactors %o A046350 def pal(n): s = str(n); return s == s[::-1] %o A046350 def ok(n): return not isprime(n) and all(pal(f) for f in primefactors(n)) %o A046350 print(list(filter(ok, range(9, 756, 2)))) # _Michael S. Branicky_, Apr 06 2021 %Y A046350 Cf. A002385, A033620, A046349, A046351. %K A046350 nonn,base %O A046350 1,1 %A A046350 _Patrick De Geest_, Jun 15 1998