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 A032624 #17 Sep 05 2024 19:28:43 %S A032624 2,10,14,20,28,38,40,50,52,58,62,64,70,80,82,100,104,110,112,118,122, %T A032624 124,142,148,160,164,170,172,178,188,194,208,218,224,230,238,244,248, %U A032624 250,260,262,274,284,292,298,308,320,338,344,352,362,364,382,398,400 %N A032624 Numbers k such that k concatenated with k+9 is a prime. %H A032624 Robert Israel, <a href="/A032624/b032624.txt">Table of n, a(n) for n = 1..10000</a> %p A032624 tcat:= (a,b) -> a*10^(1+ilog10(b))+b: %p A032624 select(t -> isprime(tcat(t,t+9)), [seq(i,i=2..1000,2)]); # _Robert Israel_, Sep 04 2024 %t A032624 Select[Range[400],PrimeQ[FromDigits[Join[IntegerDigits[#],IntegerDigits[#+9]]]]&] (* _Stefano Spezia_, Sep 04 2023 *) %Y A032624 Cf. A032614. %K A032624 nonn,base %O A032624 1,1 %A A032624 _Patrick De Geest_, May 15 1998