|
%I #8 Sep 16 2020 12:51:15
%S 12,16,20,24,42,21,48,24,153,153,9,170,170,10,209,143,33,216,192,351,
%T 338,65,13,350,420,42,14,690,1230,150,15,864,1088,240,16,16,935,1088,
%U 323,17,1062,1026,234,18,1482,1615,608,57,1660,1560,640,80,20,2226,4494
%N Irregular table read by rows: Place two n-gons with radii 1 and 2 concentrically, forming an annular area between them. Connect all the vertices with line segments that lie entirely within that area. Then T(n,k) = number of k-sided polygons in that figure for k>=3.
%C Because of symmetry, T(n,k) is divisible by n.
%C See A337700 for illustrations.
%H Lars Blomberg, <a href="/A337703/b337703.txt">Table of n, a(n) for n = 1..678</a> (rows 3-102)
%e Table begins:
%e 12
%e 16
%e 20
%e 24
%e 42,21
%e 48,24
%e 153,153,9
%e 170,170,10
%e 209,143,33
%e 216,192
%e 351,338,65,13
%e 350,420,42,14
%e 690,1230,150,15
%e 864,1088,240,16,16
%e 935,1088,323,17
%e 1062,1026,234,18
%e 1482,1615,608,57
%e 1660,1560,640,80,20
%Y Row sums are A337700. Cf. A337701, A337702.
%K nonn,tabf
%O 1,1
%A _Lars Blomberg_, Sep 16 2020
|
