A332376 - OEIS

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A332376

Total number of edges in graph formed by the straight line segments connecting the edges of an equilateral triangle with the n-1 points resulting from a subdivision of the sides into n equal pieces.

8

3, 12, 39, 54, 123, 144, 255, 282, 435, 468, 663, 702, 939, 984, 1245, 1314, 1635, 1692, 2055, 2100, 2523, 2592, 3039, 3042, 3603, 3684, 4215, 4302, 4875, 4950, 5583, 5682, 6339, 6444, 7107, 7254, 7995, 8112, 8895, 8964, 9843, 9936, 10839, 10974

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

N. J. A. Sloane, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = A092098(n) + A331782(n) - 1 (Euler's formula).

CROSSREFS

Cf. A091908, A092098 (number of cells), A331782 (number of vertices).

Equals three times A332377.

Sequence in context: A222643 A129014 A335412 * A379013 A341712 A261384

Adjacent sequences: A332373 A332374 A332375 * A332377 A332378 A332379

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Feb 13 2020

STATUS

approved