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 A341734 #12 Mar 08 2021 02:16:37 %S A341734 0,1,4,10,22,37,68,106,137,225,310,376,538,685,716,1058,1288,1471, %T A341734 1842,2170,2327,2941,3388,3734,4412,4993,5444,6306,7042,7391,8680, %U A341734 9586,10289,11585,12682,13628,15078,16381,17440,19210,20740,21899,24038,25810,27245,29613,31648,33418,35992,38305 %N A341734 a(n) = A007678(2*n)/(2*n). %C A341734 This is the number of cells in a 1/(2*n)-th sector of a regular (2*n)-gon with all diagonals drawn. See Rubinstein's illustrations in A007678. %H A341734 Scott R. Shannon, <a href="/A341734/b341734.txt">Table of n, a(n) for n = 1..71</a> %e A341734 If we divide a regular hexagon with all diagonals drawn into 6 sectors (or pizza slices), each sector contains three triangles and one quadrilateral (cf. A331450), so a(3) = A007678(6)/6 = 24/6 = 4. %Y A341734 Cf. A007678, A331450, A341735. %Y A341734 Row sums of triangle in A342268. %K A341734 nonn %O A341734 1,3 %A A341734 _Scott R. Shannon_ and _N. J. A. Sloane_, Mar 07 2021