A138727 - cp's OEIS frontend

A138727 Numbers n whose hexadecimal representation is the n-th member of the alphanumeric sequence: 1A, 2A, 3B, 4B, 5B, 6B, 7B, 8B, 8B, 8B, 1B, 2B, 3A, 4A, 5A, 6A, 7A, 8A. (A notation convention of the groups in the periodic table of the elements with 18 columns).

n	a(n)
1	26
2	42
3	59
4	75
5	91
6	107
7	123
8	139
9	139
10	139
11	27
12	43
13	58
14	74
15	90
16	106
17	122
18	138

[26, 42, 59, 75, 91, 107, 123, 139, 139, 139, 27, 43, 58, 74, 90, 106, 122, 138]