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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.

A027696 Numbers k >= 2 such that for some m >= 2, the sum of the first m k-gonal numbers is again a k-gonal number, excluding the parametric solution m = (k^2-4*k-2)/3 when k==2 (mod 3).

Table of values

n a(n)
1 3
2 4
3 6
4 8
5 10
6 11
7 14
8 17
9 30
10 41
11 43
12 50
13 60
14 88
15 145
16 276
17 322
18 374
19 823
20 1152

List of values

[3, 4, 6, 8, 10, 11, 14, 17, 30, 41, 43, 50, 60, 88, 145, 276, 322, 374, 823, 1152]

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

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