A000487Number of permutations of length n with exactly two valleys.
16, 272, 2880, 24576, 185856, 1304832, 8728576, 56520704, 357888000, 2230947840, 13754155008, 84134068224, 511780323328, 3100738912256, 18733264797696, 112949304754176, …
The first 2 terms appear at position 407,689.
…23846264338327950288419716939937510582097494459230…
…85703611816094139763446516272565828861687821301342558…
| terms | string | first position | occurrences |
|---|---|---|---|
| 1 | 16 | 40 | 10,001,877 |
| 2 | 16272 | 407,689 | 10,142 |
| 3 | 162722880 | not within 1,000,000,000 | 0 |
Searched the first 1,000,000,000 digits. Strings longer than 12 digits are not indexed.