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A320801 Regular triangle read by rows where T(n,k) is the number of nonnegative integer matrices up to row and column permutations with no zero rows or columns and k nonzero entries summing to n. 6
1, 0, 1, 0, 1, 3, 0, 1, 3, 6, 0, 1, 6, 10, 16, 0, 1, 6, 20, 30, 34, 0, 1, 9, 31, 75, 92, 90, 0, 1, 9, 45, 126, 246, 272, 211, 0, 1, 12, 60, 223, 501, 839, 823, 558, 0, 1, 12, 81, 324, 953, 1900, 2762, 2482, 1430, 0, 1, 15, 100, 491, 1611, 4033, 7120, 9299, 7629, 3908 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

Table of n, a(n) for n=1..66.

EXAMPLE

Triangle begins:

   1

   0   1

   0   1   3

   0   1   3   6

   0   1   6  10  16

   0   1   6  20  30  34

   0   1   9  31  75  92  90

   0   1   9  45 126 246 272 211

   0   1  12  60 223 501 839 823 558

CROSSREFS

Row sums are A007716. Last column is A049311.

Cf. A316980, A316983, A317533, A318805, A319616, A319721, A320796, A320808, A321194.

Sequence in context: A091867 A127158 A112367 * A035623 A248949 A325673

Adjacent sequences:  A320798 A320799 A320800 * A320802 A320803 A320804

KEYWORD

nonn,tabl

AUTHOR

Gus Wiseman, Nov 09 2018

STATUS

approved

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Last modified July 10 00:00 EDT 2020. Contains 335570 sequences. (Running on oeis4.)