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 A257604 #18 May 09 2015 14:50:22 %S A257604 5,6,7,10,12,13,14,15,18,20,21,22,23,24,25,26,28,29,30,31,34,35,36,37, %T A257604 38,39,40,41,42,44,45,46,47,48,49,50,52,53,54,55,56,58,60,61,62,63,65, %U A257604 66,68,69,70,71,72,74,75,76,77,78,79,80,82,84,85,86,87,88,90,91,92,93,94,95,96,98,100 %N A257604 Congruentful numbers. Numbers that are not congruentfree. Complement of A253278. %C A257604 These are the positive integers divisible by a congruent number given in A003273. - _Wolfdieter Lang_, May 09 2015 %e A257604 10 is in this sequence because the positive integer 10 is divisible by congruent number 5. %Y A257604 Cf. A003273, A253278. %K A257604 nonn,easy %O A257604 1,1 %A A257604 _Juri-Stepan Gerasimov_, May 06 2015