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.

A031405 Numbers k such that the continued fraction for sqrt(k) has even period 2*m and the m-th term of the periodic part is 2.

Table of values

n a(n)
1 6
2 12
3 14
4 20
5 21
6 28
7 30
8 33
9 42
10 44
11 45
12 52
13 55
14 56
15 60
16 70
17 72
18 77
19 90
20 95
21 110
22 112
23 117
24 126
25 132
26 133
27 138
28 153
29 154
30 156
31 161
32 165
33 180
34 182
35 184
36 189
37 190
38 207
39 209
40 210
41 221
42 234
43 240
44 248
45 253
46 261
47 272
48 275
49 276
50 285
51 286
52 297
53 299
54 306
55 310
56 315

List of values

[6, 12, 14, 20, 21, 28, 30, 33, 42, 44, 45, 52, 55, 56, 60, 70, 72, 77, 90, 95, 110, 112, 117, 126, 132, 133, 138, 153, 154, 156, 161, 165, 180, 182, 184, 189, 190, 207, 209, 210, 221, 234, 240, 248, 253, 261, 272, 275, 276, 285, 286, 297, 299, 306, 310, 315]

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

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