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A342268 Irregular triangle read by rows: Take a regular (2*n)-sided polygon (n>=2) with all diagonals drawn, as in A007678. Then T(n,k) = (1/(2*n))*(number of k-sided polygons in that figure) for k = 3, 4, ..., max_k. 2
1, 3, 1, 7, 3, 12, 9, 1, 23, 14, 34, 27, 7, 53, 42, 8, 3, 78, 53, 4, 1, 1, 110, 79, 29, 6, 0, 1, 136, 130, 37, 3, 2, 3, 184, 154, 35, 3, 184, 154, 35, 3, 297, 273, 76, 34, 4, 1, 389, 264, 48, 15, 449, 403, 153, 46, 7, 547, 497, 163, 69, 9, 3, 679, 519, 207, 59, 5, 2, 759, 717, 268, 71, 22, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

COMMENTS

This is a version of A331450: take the even indexed rows and divide by the number of vertices. That is, we only consider one sector (or pizza slice).

LINKS

Table of n, a(n) for n=2..76.

Scott R. Shannon, Rows 2 through 70.

EXAMPLE

Triangle begins:

1;

3, 1;

7, 3;

12, 9, 1;

23, 14;

34, 27, 7;

53, 42, 8, 3;

78, 53, 4, 1, 1;

110, 79, 29, 6, 0, 1;

136, 130, 37, 3, 2, 2;

184, 154, 35, 3;

242, 195, 81, 15, 4, 1;

297, 273, 76, 34, 4, 1;

389, 264, 48, 15;

449, 403, 153, 46, 7;

547, 497, 163, 69, 9, 3;

679, 519, 207, 59, 5, 2;

759, 717, 268, 71, 22, 5;

900, 819, 329, 100, 16, 5, 0, 0, 0, 1;

1079, 885, 271, 82, 9, 1;

...

CROSSREFS

Cf. A007678.

Row sums give A341734.

Sequence in context: A329369 A083239 A333847 * A316742 A189050 A095868

Adjacent sequences:  A342265 A342266 A342267 * A342269 A342270 A342271

KEYWORD

nonn,tabf

AUTHOR

Scott R. Shannon and N. J. A. Sloane, Mar 07 2021

STATUS

approved

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Last modified September 23 14:06 EDT 2021. Contains 347617 sequences. (Running on oeis4.)