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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.

A066957 a(n) = number of ways of placing '+' and '-' among the digits 123456789 so that the result of the expression is n, '-' before 1 IS allowed.

Table of values

n a(n)
0 22
1 43
2 18
3 41
4 18
5 40
6 24
7 39
8 18
9 46
10 17
11 38
12 27
13 38
14 24
15 43
16 18
17 39
18 23
19 37
20 23
21 43
22 25
23 36
24 32
25 36
26 25
27 44
28 25
29 35
30 34
31 31
32 26
33 37
34 24
35 35
36 32
37 32
38 27
39 37
40 31
41 26
42 34
43 34
44 29
45 42
46 27
47 27
48 35
49 26
50 28
51 35
52 29
53 33
54 30
55 26
56 23
57 29
58 32
59 25
60 33
61 30
62 24
63 34
64 22
65 26
66 32
67 30
68 25

List of values

[22, 43, 18, 41, 18, 40, 24, 39, 18, 46, 17, 38, 27, 38, 24, 43, 18, 39, 23, 37, 23, 43, 25, 36, 32, 36, 25, 44, 25, 35, 34, 31, 26, 37, 24, 35, 32, 32, 27, 37, 31, 26, 34, 34, 29, 42, 27, 27, 35, 26, 28, 35, 29, 33, 30, 26, 23, 29, 32, 25, 33, 30, 24, 34, 22, 26, 32, 30, 25]

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

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