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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A227308 Given an equilateral triangular grid with side n consisting of n(n+1)/2 points, a(n) is the maximum number of points that can be painted so that, if any 3 of the painted ones are chosen, they do not form an equilateral triangle with sides parallel to the grid.

Table of values

n a(n)
1 1
2 2
3 4
4 6
5 8
6 12
7 14
8 18
9 22
10 26
11 30
12 34
13 39
14 44
15 49

List of values

[1, 2, 4, 6, 8, 12, 14, 18, 22, 26, 30, 34, 39, 44, 49]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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