|
Search: id:A120118
|
|
|
| A120118 |
|
a(n) is the number of binary strings of length n such that no subsequence of length 5 or less contains 3 or more ones. |
|
+0
3
|
|
| 2, 4, 7, 11, 16, 26, 43, 71, 116, 186, 300, 487, 792, 1287, 2087, 3382, 5484, 8898, 14438, 23423, 37993, 61625, 99965, 162165, 263065, 426736, 692229, 1122903, 1821538, 2954849, 4793266, 7775472, 12613097, 20460538, 33190414, 53840404
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
FORMULA
|
a(n) = a(n-1) + a(n-3) + 2a(n-5) - a(n-8) - a(n-10)
|
|
EXAMPLE
|
This sequence is similar to A118647 - where no subsequence of length 4 contains 3 ones. It is obvious that the first 4 terms of these two sequences are the same. There are only 3 sequences of length 5 that contain 3 ones such that no subsequence of length 4 contains 3 ones: 10101, 11001, 10011. Hence the fifth term for this sequence is 3 less than the corresponding term of A118647.
|
|
CROSSREFS
|
Sequence in context: A011912 A063676 A099385 this_sequence A108895 A146929 A146921
Adjacent sequences: A120115 A120116 A120117 this_sequence A120119 A120120 A120121
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Tanya Khovanova (tanyakh(AT)yahoo.com), Aug 15 2006, Oct 11 2006
|
|
|
Search completed in 0.002 seconds
|
