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A136102 Triangle read by rows, in which rows give signatures for Ferrers boards fitting inside staircases coded 1, 2, 12, 360, 75600, ... (see A006939). 2
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

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

REFERENCES

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

LINKS

Table of n, a(n) for n=1..60.

EXAMPLE

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

CROSSREFS

Cf. A000041 A000108 A006939 A025487.

Sequence in context: A058553 A112179 A038067 * A279586 A275762 A139248

Adjacent sequences:  A136099 A136100 A136101 * A136103 A136104 A136105

KEYWORD

easy,nonn,tabf

AUTHOR

Alford Arnold, Jan 12 2008

STATUS

approved

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Last modified February 24 17:22 EST 2018. Contains 299624 sequences. (Running on oeis4.)