login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A331713 Number of nonnegative integer matrices with distinct nonzero rows, total sum n each column with the same sum and columns in nonincreasing lexicographic order. 2
1, 3, 7, 18, 21, 147, 77, 1119, 2270, 12273, 1089, 464200, 4229, 4148223, 32941976, 159812905, 66153, 10211281004, 263321, 205923976532, 2439257062679, 3086915165084, 4199061, 1526043270802300, 311419986358517, 4817701809545446, 621665561741298232, 1898993198795136209 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The condition that the columns be in nonincreasing order is equivalent to considering nonequivalent matrices up to permutation of columns.

LINKS

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

FORMULA

a(n) = Sum_{d|n} A331572(n/d, d).

EXAMPLE

The a(2) = 3 matrices are:

  [1 0]  [1 1]  [2]

  [0 1]

CROSSREFS

Cf. A331572.

Sequence in context: A222452 A218165 A102329 * A327321 A069143 A097007

Adjacent sequences:  A331710 A331711 A331712 * A331714 A331715 A331716

KEYWORD

nonn

AUTHOR

Andrew Howroyd, Jan 25 2020

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 16 20:51 EDT 2021. Contains 347473 sequences. (Running on oeis4.)