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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.

A187986 Number of nondecreasing arrangements of n numbers x(i) in -(n+5)..(n+5) with the sum of sign(x(i))*2^|x(i)| zero.

Table of values

n a(n)
1 0
2 7
3 15
4 60
5 222
6 746
7 2742
8 9689
9 34588
10 124062
11 443469
12 1591177
13 5710783
14 20514746
15 73779819
16 265523140
17 956384656
18 3447285428
19 12433999199
20 44877035870
21 162066465738
22 585603996081
23 2117103447068
24 7657611562951
25 27710598382843
26 100320181906860
27 363337451934873
28 1316442508560564

List of values

[0, 7, 15, 60, 222, 746, 2742, 9689, 34588, 124062, 443469, 1591177, 5710783, 20514746, 73779819, 265523140, 956384656, 3447285428, 12433999199, 44877035870, 162066465738, 585603996081, 2117103447068, 7657611562951, 27710598382843, 100320181906860, 363337451934873, 1316442508560564]

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

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