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A077588 Maximum number of regions the plane is divided into by n triangles. +0
4
1, 2, 8, 20, 38, 62, 92, 128, 170, 218, 272, 332, 398, 470, 548, 632, 722, 818, 920, 1028, 1142, 1262, 1388, 1520, 1658, 1802, 1952, 2108, 2270, 2438, 2612, 2792, 2978, 3170, 3368, 3572, 3782, 3998, 4220, 4448, 4682, 4922, 5168, 5420, 5678, 5942, 6212 (list; graph; listen)
OFFSET

0,2

COMMENT

a(n) = A096777(3*n-1) for n>0. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Dec 29 2007

FORMULA

a(n) = 3n^2 - 3n + 2 except when n = 0.

Nearest integer to sum(k>=n, 1/k^2)/sum(k>=n, 1/k^4) - Benoit Cloitre (benoit7848c(AT)orange.fr), Jun 12 2003

EXAMPLE

a(2) = 8 because a Jewish star has 6 points, an interior hexagon and the exterior.

CROSSREFS

Cf. A077591.

Sequence in context: A031114 A130238 A038460 this_sequence A025219 A032767 A032633

Adjacent sequences: A077585 A077586 A077587 this_sequence A077589 A077590 A077591

KEYWORD

easy,nonn

AUTHOR

Joshua Zucker and the Castilleja School mathcounts club (joshua.zucker(AT)stanfordalumni.org), Nov 07 2002

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Last modified November 27 22:38 EST 2009. Contains 167602 sequences.


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