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 A382393 #10 Mar 30 2025 16:26:14 %S A382393 2,3,4,5,6,7,8,9,10,11,12,14,15,16,17,18,19,22,23,25,26,28,29,30,31, %T A382393 32,33,36,38,39,40,42,43,44,45,47,49,51,52,53,56,58,59,60,61,64,65,66, %U A382393 67,70,72,74,75,77,78,80,81,82,84,85,86,87,91,93,94,95,98,99,100 %N A382393 Positive integers k such that 6*k - 1 is prime for k != 1 (mod 5) and (6*k - 1)/5 is prime for k == 1 (mod 5). %C A382393 For all elements of this sequence, there are no pairs (x,y) of positive integers with x > 1 such that a(n)=6*x*y+x-y. %o A382393 (PARI) select(k->isprime((6*k-1)/(5-4*!(k==Mod(1,5)))), vector(100,i,i)) %Y A382393 Cf. A024898, A024899. %K A382393 nonn %O A382393 1,1 %A A382393 _V. Barbera_, Mar 23 2025