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A194497 Number of ways to arrange 7 nonattacking queens on the lower triangle of an n X n board. 1
0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 1210, 27198, 322782, 2564988, 15372702, 74615814, 306900410, 1105651074, 3569169990, 10512880400, 28628691842, 72880455042, 174895586328, 398556484840, 867314768878, 1811576604968, 3646385889888 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,10

COMMENTS

Column 7 of A194498.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..28

EXAMPLE

Some solutions for 10 X 10:

  0                    0                    0

  0 0                  0 0                  0 0

  0 0 0                0 0 0                0 0 0

  0 1 0 0              0 1 0 0              0 0 0 1

  0 0 0 1 0            0 0 0 1 0            1 0 0 0 0

  1 0 0 0 0 0          0 0 0 0 0 1          0 0 1 0 0 0

  0 0 0 0 0 0 1        1 0 0 0 0 0 0        0 0 0 0 0 1 0

  0 0 0 0 1 0 0 0      0 0 1 0 0 0 0 0      0 1 0 0 0 0 0 0

  0 0 1 0 0 0 0 0 0    0 0 0 0 1 0 0 0 0    0 0 0 0 0 0 1 0 0

  0 0 0 0 0 1 0 0 0 0  0 0 0 0 0 0 1 0 0 0  0 0 0 0 1 0 0 0 0 0

CROSSREFS

Sequence in context: A233252 A249849 A027879 * A287226 A015108 A070065

Adjacent sequences:  A194494 A194495 A194496 * A194498 A194499 A194500

KEYWORD

nonn

AUTHOR

R. H. Hardin, Aug 26 2011

STATUS

approved

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Last modified January 19 23:39 EST 2022. Contains 350467 sequences. (Running on oeis4.)