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 A349773 #18 Dec 23 2021 12:38:19 %S A349773 16653,16836,17020,17205,17391,27495,29890,30135,50721,51040,51360, %T A349773 51681,70125,81003,81406,84255,84666,85078,85491,85905,89676,90100, %U A349773 110215,110685,111156,142311,181503,214185,222111,222778,305371,306153,344865,345696,355746,356590 %N A349773 Numbers that start a run of four consecutive triangular numbers with four distinct prime factors. %e A349773 a(1) = 16653 because 16653 is the smallest number in the first set of four consecutive triangular numbers with four distinct prime factors, i.e., 16653 = 3*7*13*61, 16836 = 2^2*3*23*61, 17020 = 2^2*5*23*37, 17205 = 3*5*31*37. %t A349773 t[n_] := n*(n + 1)/2; q[n_] := PrimeNu[n] == 4; Select[Partition[t /@ Range[1000], 4, 1], AllTrue[#, q] &][[;; , 1]] (* _Amiram Eldar_, Nov 29 2021 *) %Y A349773 Cf. A000217, A128905, A349539. %K A349773 nonn %O A349773 1,1 %A A349773 _Shyam Sunder Gupta_, Nov 29 2021