2. 23,45,89,177, ?
3. -6,-8,0,32,120, ?
4. 1,2,3,4,8,10,14,20,22, ?
5. 1,6,21,52,105, ?
6. 1,3,12,76, ?
7. 1,6,18,44,90,174,294,472, ?
8. 2,3,6,10,11,14,18,19,22, ?
9. 2,3,5,7,13,15,21,23,27, ?
10. 1,2,5,9,16,26, ?
11. 2,4,3,6,10,7,14,16,15,18,22,19, ?
12. 2,4,5,6,9,10,15,16,20, ?
13. 4,1,4,2,1,3,5, ?
14. 6,21,105,301,1221, ?
15. 2,2,1,3,2,3,4,2,6,5,2, ?
16. 1,8,24,64,126,202, ?
17. 36, 864, 21060, 544320, ?
18. 2,7,17,31,59,83,125, ?
19. 2,6,20,70,252,924,3432, ?
20. 1, 2, 9, 48, 300, 2160, ?
