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 A176590 #9 Feb 08 2025 23:35:26 %S A176590 1,2,5,6,8,10,11,12,14,15,16,17,18,20,22,23,24,26,27,28,29,30,32,33, %T A176590 34,35,36,38,40,41,42,44,45,46,47,49,50,51,52,53,54,55,56,57,58,59,60, %U A176590 61,62,63,64,65,66,68,69,70,71,72,74,75,76,77,78,80,81,82,83,84,85,86,87,88 %N A176590 Numbers k such that both concatenation of divisors of k and reverse concatenation of divisors of k are nonprime. %C A176590 Numbers k such that both A037278(k) and A176558(k) are nonprime. %F A176590 Intersection of A176554 and A175354. - _Jason Yuen_, Feb 08 2025 %e A176590 10 is a term; divisors of 10: 1, 2, 5, 10; both concatenation of divisors 12510 and reverse concatenation of divisors 10521 are nonprime numbers. %e A176590 Sequence of corresponding values of concatenations of divisors of a(n): 1, 12, 15, 1236, 1248, 12510, 111, ... %e A176590 Sequence of corresponding values of reverse concatenations of divisors of a(n): 1, 21, 51, 6321, 8421, 10521, 111, ... %Y A176590 Cf. A037278, A176558, A176554, A175354, A176589. %K A176590 nonn,base %O A176590 1,2 %A A176590 _Jaroslav Krizek_, Apr 21 2010 %E A176590 Extended and revised by _Charles R Greathouse IV_, Apr 24 2010