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 A375287 #29 Aug 11 2024 11:52:28 %S A375287 6,30,14,210,230,20,2310,7314,644,33,30030,254540,37960,1308,54, %T A375287 510510,11243154,1042404,134043,2664,91,9699690,965009045,323567034, %U A375287 21871365,357642,6850,142 %N A375287 Square array T(n, k), n > 1 and k >= 1, read by antidiagonals in ascending order, give the smallest number that starts a sequence of exactly k consecutive numbers, each having exactly n distinct prime factors (counted without multiplicity), or -1 if no such number exists. %C A375287 All positive terms are composite. %F A375287 T(n,1) = A002110(n) for n > 1. %e A375287 T(2,3) = 20 = 2^2 * 5, because both 21 and 22 have the same omega. Thus, 20 is the starting number of a run of 3 numbers that each have same omega, i.e. 2. No lesser number has this property, so T(2,3) = 20. %e A375287 Table begins (upper left corner = T(2,1)): %e A375287 6 14 20 33 ... %e A375287 30 230 644 1308 ... %e A375287 210 7314 37960 134043 ... %e A375287 2310 254540 1042404 21871365 ... %e A375287 30030 11243154 323567034 7933641735 ... %e A375287 ... ... ... ... ... %Y A375287 Cf. A001221, A002110 (col 1), A002808, A006049 (row 1), A006073, A045932-A045938. %K A375287 sign,tabl,more %O A375287 2,1 %A A375287 _Jean-Marc Rebert_, Aug 10 2024