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.

A207338 Triangle read by rows in which row n lists the prime factors of n with repetition, with a(1) = 1, but with the primes of the form 4k + 1 multiplied by -1.

Table of values

n a(n)
1 1
2 2
3 3
4 2
5 2
6 -5
7 2
8 3
9 7
10 2
11 2
12 2
13 3
14 3
15 2
16 -5
17 11
18 2
19 2
20 3
21 -13
22 2
23 7
24 3
25 -5
26 2
27 2
28 2
29 2
30 -17
31 2
32 3
33 3
34 19
35 2
36 2
37 -5
38 3
39 7
40 2
41 11
42 23
43 2
44 2
45 2
46 3
47 -5
48 -5
49 2
50 -13
51 3
52 3
53 3
54 2
55 2
56 7
57 -29
58 2
59 3
60 -5
61 31
62 2
63 2
64 2
65 2
66 2
67 3
68 11
69 2
70 -17
71 -5
72 7
73 2
74 2
75 3
76 3
77 -37

List of values

[1, 2, 3, 2, 2, -5, 2, 3, 7, 2, 2, 2, 3, 3, 2, -5, 11, 2, 2, 3, -13, 2, 7, 3, -5, 2, 2, 2, 2, -17, 2, 3, 3, 19, 2, 2, -5, 3, 7, 2, 11, 23, 2, 2, 2, 3, -5, -5, 2, -13, 3, 3, 3, 2, 2, 7, -29, 2, 3, -5, 31, 2, 2, 2, 2, 2, 3, 11, 2, -17, -5, 7, 2, 2, 3, 3, -37]

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

Content is available under The OEIS End-User License Agreement.