A000108Catalan numbers: C(n) = binomial(2n,n)/(n+1) = (2n)!/(n!(n+1)!).
1, 1, 2, 5, 14, 42, 132, 429, 1430, 4862, 16796, 58786, 208012, 742900, 2674440, 9694845, …
The first 3 terms appear at position 709.
1415926535897932384626433…
…40628620899862803482534211706798214808651328230664…
…792279689258923542019956112129021960864034418159813…
…6205696602405803815019351125338243003558764024749647…
…988552240677107478132966112514244409425462058656056386…
…30351534821461583697904411251442242557805052225321619586…
| terms | string | first position | occurrences |
|---|---|---|---|
| 1 | 1 | 1 | 99,997,334 |
| 2 | 11 | 94 | 9,997,964 |
| 3 | 112 | 709 | 1,000,085 |
| 4 | 1125 | 1,349 | 100,120 |
| 5 | 112514 | 207,613 | 1,002 |
| 6 | 11251442 | 75,744,697 | 12 |
| 7 | 11251442132 | not within 1,000,000,000 | 0 |
Searched the first 1,000,000,000 digits. Strings longer than 12 digits are not indexed.