The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 2 |
| 5 | 2 |
| 6 | 3 |
| 7 | 3 |
| 8 | 4 |
| 9 | 3 |
| 10 | 3 |
| 11 | 3 |
| 12 | 4 |
| 13 | 4 |
| 14 | 5 |
| 15 | 5 |
| 16 | 5 |
| 17 | 5 |
| 18 | 6 |
| 19 | 6 |
| 20 | 7 |
| 21 | 7 |
| 22 | 7 |
| 23 | 7 |
| 24 | 8 |
| 25 | 7 |
| 26 | 7 |
| 27 | 7 |
| 28 | 7 |
| 29 | 7 |
| 30 | 8 |
| 31 | 8 |
| 32 | 9 |
| 33 | 9 |
| 34 | 9 |
| 35 | 9 |
| 36 | 9 |
| 37 | 9 |
| 38 | 10 |
| 39 | 10 |
| 40 | 10 |
| 41 | 10 |
| 42 | 11 |
| 43 | 11 |
| 44 | 12 |
| 45 | 12 |
| 46 | 12 |
| 47 | 12 |
| 48 | 13 |
| 49 | 12 |
| 50 | 12 |
| 51 | 12 |
| 52 | 12 |
| 53 | 12 |
| 54 | 13 |
| 55 | 13 |
| 56 | 13 |
| 57 | 13 |
| 58 | 13 |
| 59 | 13 |
| 60 | 14 |
| 61 | 14 |
| 62 | 15 |
| 63 | 15 |
| 64 | 15 |
| 65 | 15 |
| 66 | 15 |
| 67 | 15 |
| 68 | 16 |
| 69 | 16 |
| 70 | 16 |
| 71 | 16 |
| 72 | 17 |
| 73 | 17 |
| 74 | 18 |
| 75 | 18 |
| 76 | 18 |
| 77 | 18 |
| 78 | 18 |
| 79 | 18 |
| 80 | 19 |
| 81 | 19 |
| 82 | 19 |
[0,1,2,2,2,3,3,4,3,3,3,4,4,5,5,5,5,6,6,7,7,7,7,8, 7,7,7,7,7,8,8,9,9,9,9,9,9,10,10,10,10,11,11,12,12, 12,12,13,12,12,12,12,12,13,13,13,13,13,13,14,14, 15,15,15,15,15,15,16,16,16,16,17,17,18,18,18,18, 18,18,19,19,19] |