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 A367323 #15 Jan 06 2024 12:01:25 %S A367323 1,12,4,75,56,11,252,340,170,24,715,1120,1161,408,50,1572,3264,3900, %T A367323 2268,868,80,3109,6264,10741,8208,5594,1488,154,5676,13968,22380, %U A367323 20832,18396,9312,2754,220,9291,22904,44491,44640,48462,31552,16858,4220,375 %N A367323 Table read by antidiagonals: Place k equally spaced points on each side of a regular n-gon and join every pair of the n*(k+1) boundary points by a chord; T(n,k) (n >= 3, k >= 0) gives the number of regions in the resulting planar graph. %C A367323 See A367322 and the cross references for further images of the n-gons. %H A367323 Scott R. Shannon, <a href="/A367323/a367323.png">Image for T(12,2)</a>. %H A367323 Scott R. Shannon, <a href="/A367323/a367323_1.png">Image for T(23,1)</a>. %F A367323 T(n,k) = A367324(n,k) - A367322(n,k) + 1 (Euler). %e A367323 The table begins: %e A367323 1, 12, 75, 252, 715, 1572, 3109, 5676, 9291, 14556, 22081, 32502, 44935, 62868, ... %e A367323 4, 56, 340, 1120, 3264, 6264, 13968, 22904, 38748, 58256, 95656, 120960, ... %e A367323 11, 170, 1161, 3900, 10741, 22380, 44491, 76610, 126336, 194070, 290651, ... %e A367323 24, 408, 2268, 8208, 20832, 44640, 89214, 154752, 249906, 390012, 590658, ... %e A367323 50, 868, 5594, 18396, 48462, 101794, 195714, 336504, 549704, 841890, 1249676, ... %e A367323 80, 1488, 9312, 31552, 83432, 174816, 339816, 584176, 953416, 1463936, 2173976, ... %e A367323 154, 2754, 16858, 55098, 142318, 298350, 568162, 975294, 1585666, 2426292, ... %e A367323 220, 4220, 25220, 84280, 217800, 456640, 873090, 1501520, 2436020, 3736540, ... %e A367323 375, 6732, 39887, 129492, 330903, 692648, 1311443, 2248840, 3645885, 5574756, ... %e A367323 444, 9000, 52056, 178200, 462504, 963576, 1854432, 3180816, 5157612, 7906080, ... %e A367323 781, 13962, 80783, 261222, 662663, 1385332, 2613521, 4478188, 7246331, ... %e A367323 952, 18676, 107142, 352828, 891870, 1870876, 3525494, 6053768, 9778370, ... %e A367323 1456, 25860, 146956, 474000, 1196116, 2498010, 4700776, 8050080, 13008106, ... %e A367323 1696, 33152, 188000, 615328, 1547792, 3244000, 6095600, 10458560, 16876160, ... %e A367323 2500, 44098, 247334, 795634, 1999762, 4173296, 7838004, 13416740, ... %e A367323 2466, 52236, 302148, 991800, 2502000, 5229396, 9846234, ... %e A367323 4029, 70604, 391781, 1258028, 3152101, 6574000, 12328417, ... %e A367323 4500, 86240, 475800, 1546280, 3865240, 8085040, 15143880, ... %e A367323 6175, 107562, 591655, 1897182, 4741633, 9883986, ... %e A367323 6820, 129448, 706288, 2288880, 5703698, 11924132, ... %e A367323 9086, 157412, 859718, 2753192, 6866858, 14307932, ... %e A367323 9024, 181152, 1001640, 3254160, 8117304, ... %e A367323 12926, 222850, 1209776, 3870250, 9636276, ... %e A367323 . %e A367323 . %e A367323 . %Y A367323 Cf. A367322 (vertices), A367324 (edges), A092867 (1st row), A255011 (2nd row), A331929 (3rd row), A331931 (4th row), A329713 (5th row), A333075 (6th row), A332421 (7th row), A333139 (8th row), A007678 (1st column). %K A367323 nonn,tabl %O A367323 3,2 %A A367323 _Scott R. Shannon_ and _N. J. A. Sloane_, Nov 14 2023