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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.

A138858 a(n) = least square such that the subsets of {a(1),...,a(n)} sum to 2^n different values.

Table of values

n a(n)
1 1
2 4
3 9
4 16
5 36
6 81
7 144
8 324
9 625
10 1156
11 2401
12 4900
13 9801
14 19600
15 39204
16 78400
17 156816
18 313600
19 627264
20 1254400
21 2509056
22 5022081
23 10042561
24 20088324
25 40182921
26 80371225
27 160731684
28 321484900
29 642977449
30 1285939600
31 2571909796
32 5143901841
33 10287842041
34 20575607364
35 41151368164
36 82303003225
37 164606284089
38 329212012900
39 658425136356
40 1316850346681
41 2633700545424
42 5267401386724

List of values

[1, 4, 9, 16, 36, 81, 144, 324, 625, 1156, 2401, 4900, 9801, 19600, 39204, 78400, 156816, 313600, 627264, 1254400, 2509056, 5022081, 10042561, 20088324, 40182921, 80371225, 160731684, 321484900, 642977449, 1285939600, 2571909796, 5143901841, 10287842041, 20575607364, 41151368164, 82303003225, 164606284089, 329212012900, 658425136356, 1316850346681, 2633700545424, 5267401386724]

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

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