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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.

A193697 Number of arrays of -3..3 integers x(1..n) with every x(i) in a subsequence of length 1, 2 or 3 with sum zero.

Table of values

n a(n)
1 1
2 7
3 43
4 181
5 827
6 3773
7 17197
8 78407
9 357403
10 1629369
11 7428007
12 33862711
13 154372795
14 703751937
15 3208252657
16 14625730979
17 66675552791
18 303959466209
19 1385685646663
20 6317041957501
21 28798031581467
22 131284013681727
23 598495497977845
24 2728411869163663
25 12438241145358561

List of values

[1, 7, 43, 181, 827, 3773, 17197, 78407, 357403, 1629369, 7428007, 33862711, 154372795, 703751937, 3208252657, 14625730979, 66675552791, 303959466209, 1385685646663, 6317041957501, 28798031581467, 131284013681727, 598495497977845, 2728411869163663, 12438241145358561]

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

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