Make 1 3 5 7 9 11 13 15 17 6 4 2 12 10 8 18 16 14 for 90 numbers

The pattern you've shown is two interleaved sequences:

Odd numbers: 1, 3, 5, 7, 9, 11, 13, 15, 17, ...
Even numbers: 6, 4, 2, 12, 10, 8, 18, 16, 14, ...

The even sequence groups in descending triplets, each group starting 6 higher than the previous: (6,4,2), (12,10,8), (18,16,14), (24,22,20), ...

Here is the full sequence for 90 numbers (45 odd + 45 even, interleaved):

1   3   5   7   9   11  13  15  17
6   4   2   12  10  8   18  16  14

19  21  23  25  27  29  31  33  35
24  22  20  30  28  26  36  34  32

37  39  41  43  45  47  49  51  53
42  40  38  48  46  44  54  52  50

55  57  59  61  63  65  67  69  71
60  58  56  66  64  62  72  70  68

73  75  77  79  81  83  85  87  89
78  76  74  84  82  80  90  88  86

Full flat list (90 numbers):

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

Key rules used:

Each block of 18 numbers = 9 consecutive odd numbers, then 9 even numbers in 3 descending triplets
Each new block picks up where the previous left off (odds continue from 19, 37, 55, 73; even triplets continue from 24, 42, 60, 78)
All 90 numbers from 1-90 appear exactly once

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