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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.

A120411 If A is a set of integers, the (2-fold) sumset consists of all the numbers which can be written as the sum of two (not necessarily distinct) elements in A. a(n) is the number of subsets of [1,2n] which are sumsets for some set of positive integers.

Table of values

n a(n)
1 1
2 3
3 7
4 15
5 30
6 59
7 114
8 219
9 416
10 783
11 1461
12 2722
13 5048
14 9341
15 17243
16 31674
17 58037
18 105936
19 192522
20 348832

List of values

[1, 3, 7, 15, 30, 59, 114, 219, 416, 783, 1461, 2722, 5048, 9341, 17243, 31674, 58037, 105936, 192522, 348832]

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

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