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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.

A277215 a(n) is the smallest even number not congruent to 1 modulo 3 that starts a (2n+1)-element alternating sequence of x/2 and (3x+1) iterations ending in the maximum of its Collatz trajectory.

Table of values

n a(n)
0 0
1 26
2 6
3 14
4 30
5 1214
6 1662
7 254
8 510
9 1022
10 2046
11 28670
12 40958
13 180222
14 32766
15 65534
16 131070
17 1835006
18 5767166
19 1048574
20 2097150
21 4194302
22 8388606
23 16777214
24 33554430
25 469762046
26 671088638
27 268435454
28 536870910
29 7516192766
30 2147483646
31 4294967294
32 8589934590
33 17179869182
34 34359738366
35 755914244094

List of values

[0, 26, 6, 14, 30, 1214, 1662, 254, 510, 1022, 2046, 28670, 40958, 180222, 32766, 65534, 131070, 1835006, 5767166, 1048574, 2097150, 4194302, 8388606, 16777214, 33554430, 469762046, 671088638, 268435454, 536870910, 7516192766, 2147483646, 4294967294, 8589934590, 17179869182, 34359738366, 755914244094]

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

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