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 A302490 #16 Apr 27 2018 17:16:17 %S A302490 0,2,2,1,2,2,2,3,1,3,3,3,3,4,3,1,2,2,2,3,3,3,2,2,1,3,4,3,2,4,2,3,5,4, %T A302490 4,2,3,3,3,3,3,3,3,4,3,3,3,3,1,4,4,5,3,4,5,3,4 %N A302490 Fewest number of distinct prime factors in any product of a_1*a_2*...*a_t where n = a_1 < a_2 < ... < a_t = A006255(n) and the product is square. %C A302490 a(n^2) = A001221(n). %e A302490 a(14) = 4 because 14 * 15 * 16 * 18 * 20 * 21 has four distinct prime factors (2, 3, 5, and 7) and no other square product of a strictly increasing sequence starting at 14 and ending at 21 has fewer distinct prime factors. %Y A302490 Cf. A001221, A006255, A280244. %Y A302490 Cf. A066400, A245530. %K A302490 nonn,more %O A302490 1,2 %A A302490 _Peter Kagey_, Apr 08 2018