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.

A123402 Combining the conditional divide-by-two concept from Collatz sequences with Pascal's triangle, one can construct a new kind of triangle. Start with an initial row of just 4. To compute subsequent rows, start by appending a zero to the beginning and end of the previous row. Like Pascal's triangle, add adjacent terms of the previous row to create each of the subsequent terms. The only change is that each new term is divided by two if it is even.

Table of values

n a(n)
0 4
1 2
2 2
3 1
4 2
5 1
6 1
7 3
8 3
9 1
10 1
11 2
12 3
13 2
14 1
15 1
16 3
17 5
18 5
19 3
20 1
21 1
22 2
23 4
24 5
25 4
26 2
27 1
28 1
29 3
30 3
31 9
32 9
33 3
34 3
35 1
36 1
37 2
38 3
39 6
40 9
41 6
42 3
43 2
44 1
45 1
46 3
47 5
48 9
49 15
50 15
51 9
52 5
53 3
54 1
55 1
56 2
57 4
58 7
59 12
60 15
61 12
62 7
63 4
64 2
65 1
66 1
67 3
68 3
69 11
70 19
71 27
72 27
73 19
74 11
75 3
76 3
77 1
78 1
79 2
80 3
81 7
82 15
83 23
84 27
85 23
86 15
87 7
88 3
89 2
90 1
91 1
92 3
93 5
94 5
95 11
96 19

List of values

[4, 2, 2, 1, 2, 1, 1, 3, 3, 1, 1, 2, 3, 2, 1, 1, 3, 5, 5, 3, 1, 1, 2, 4, 5, 4, 2, 1, 1, 3, 3, 9, 9, 3, 3, 1, 1, 2, 3, 6, 9, 6, 3, 2, 1, 1, 3, 5, 9, 15, 15, 9, 5, 3, 1, 1, 2, 4, 7, 12, 15, 12, 7, 4, 2, 1, 1, 3, 3, 11, 19, 27, 27, 19, 11, 3, 3, 1, 1, 2, 3, 7, 15, 23, 27, 23, 15, 7, 3, 2, 1, 1, 3, 5, 5, 11, 19]