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 A328793 #14 Oct 30 2019 02:23:50 %S A328793 2,4,3,5,4,7,6,5,8,7,6,10,9,8,7,11,10,9,13,8,11,10,14,13,9,12,11,16, %T A328793 15,14,10,13,12,16,15,11,14,19,18,13,17,16,12,15,20,19,14,17,13,16,21, %U A328793 20,19,15,18,14,22,17,21,20,16,19,25,24,15,18,22,21,17 %N A328793 Least k such that there exists an equilateral triangle of side length sqrt(A003136(n)) with vertices in an equilateral triangular array of points with k rows. %C A328793 a(A024610(n) - 1) = n + 1 for all n > 0, and %C A328793 a(A024610(n) + k) > n + 1 for all n > 0, k >= 0. %H A328793 Peter Kagey, <a href="/A328793/b328793.txt">Table of n, a(n) for n = 1..10000</a> %e A328793 For n = 2, there exists an equilateral triangle with side length sqrt(A003136(2)) = sqrt(3) and vertices on equilateral triangular array with a(2) = 4 rows: %e A328793 o %e A328793 * o %e A328793 o o * %e A328793 o * o o. %e A328793 However there is no equilateral triangle of side length sqrt(3) with vertices on a smaller triangular array with three or fewer rows. %Y A328793 Cf. A003136, A024610, A328787. %K A328793 nonn,look %O A328793 1,1 %A A328793 _Peter Kagey_, Oct 27 2019