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A337703 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. 4
12, 16, 20, 24, 42, 21, 48, 24, 153, 153, 9, 170, 170, 10, 209, 143, 33, 216, 192, 351, 338, 65, 13, 350, 420, 42, 14, 690, 1230, 150, 15, 864, 1088, 240, 16, 16, 935, 1088, 323, 17, 1062, 1026, 234, 18, 1482, 1615, 608, 57, 1660, 1560, 640, 80, 20, 2226, 4494 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Because of symmetry, T(n,k) is divisible by n.

See A337700 for illustrations.

LINKS

Lars Blomberg, Table of n, a(n) for n = 1..678 (rows 3-102)

EXAMPLE

Table begins:

12

16

20

24

42,21

48,24

153,153,9

170,170,10

209,143,33

216,192

351,338,65,13

350,420,42,14

690,1230,150,15

864,1088,240,16,16

935,1088,323,17

1062,1026,234,18

1482,1615,608,57

1660,1560,640,80,20

CROSSREFS

Row sums are A337700. Cf. A337701, A337702.

Sequence in context: A225071 A210577 A231903 * A337700 A243538 A183052

Adjacent sequences:  A337700 A337701 A337702 * A337704 A337705 A337706

KEYWORD

nonn,tabf

AUTHOR

Lars Blomberg, Sep 16 2020

STATUS

approved

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Last modified January 26 07:04 EST 2022. Contains 350572 sequences. (Running on oeis4.)