A136102 Triangle read by rows, in which rows give signatures for Ferrers boards fitting inside staircases coded 1, 2, 12, 360, 75600, ... (see A006939).

1, 1, 2, 1, 2, 4, 6, 12, 1, 2, 4, 6, 8, 12, 24, 30, 36, 60, 72, 120, 180, 360, 1, 2, 4, 6, 8, 12, 16, 24, 30, 36, 48, 60, 72, 120, 144, 180, 210, 216, 240, 360, 420, 32, 720, 840, 900, 1080, 1260, 1680, 1800, 2160, 2520, 3600, 5040, 5400, 6300, 7560, 10800, 12600

Offset: 1

Author

Alford Arnold, Jan 12 2008

Keywords

• easy
• nonn
• tabf

Comments

The number of signatures on each row is 1 2 5 14 42 132 ... cf. A000108.

Examples

			The irregular array begins
1
1 2
1 2 4 6 12
1 2 4 6 8 12 24 30 36 60 72 120 180 360
		

References

• G. E. Andrews and K. Eriksson, Integer Partitions, Cambridge Univ. Press, 2004. page 22 Exer. 33.

Crossrefs

Cf. A000041 A000108 A006939 A025487.