cp's OEIS Frontend

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.

A316657 For any n >= 0 with base-5 expansion Sum_{k=0..w} d_k * 5^k, let f(n) = Sum_{k=0..w} [d_k > 0] * (2 + i)^k * i^(d_k - 1) (where [] is an Iverson bracket and i denotes the imaginary unit); a(n) equals the real part of f(n).

Table of values

n a(n)
0 0
1 1
2 0
3 -1
4 0
5 2
6 3
7 2
8 1
9 2
10 -1
11 0
12 -1
13 -2
14 -1
15 -2
16 -1
17 -2
18 -3
19 -2
20 1
21 2
22 1
23 0
24 1
25 3
26 4
27 3
28 2
29 3
30 5
31 6
32 5
33 4
34 5
35 2
36 3
37 2
38 1
39 2
40 1
41 2
42 1
43 0
44 1
45 4
46 5
47 4
48 3
49 4
50 -4
51 -3
52 -4
53 -5
54 -4
55 -2
56 -1
57 -2
58 -3
59 -2
60 -5
61 -4
62 -5
63 -6
64 -5
65 -6
66 -5
67 -6
68 -7
69 -6
70 -3
71 -2
72 -3
73 -4
74 -3

List of values

[0, 1, 0, -1, 0, 2, 3, 2, 1, 2, -1, 0, -1, -2, -1, -2, -1, -2, -3, -2, 1, 2, 1, 0, 1, 3, 4, 3, 2, 3, 5, 6, 5, 4, 5, 2, 3, 2, 1, 2, 1, 2, 1, 0, 1, 4, 5, 4, 3, 4, -4, -3, -4, -5, -4, -2, -1, -2, -3, -2, -5, -4, -5, -6, -5, -6, -5, -6, -7, -6, -3, -2, -3, -4, -3]