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!)
A332729 Number of nonnegative integer n X n matrices with row and column sums 2 and sum of entries below the main diagonal n - 1. 2
1, 1, 11, 114, 2438, 73120, 3107640, 175157568, 12683256458, 1146644890542, 126603925984322, 16764298017398342, 2622239904802101734, 478350006311298468126, 100655530463934465864626, 24200010145455307873369888, 6592700960401481917596215614, 2020180735699844322843722782402 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Jean-François Alcover, Table of n, a(n) for n = 1..40 (all terms from Andrew Howroyd)

EXAMPLE

The a(2) = 1 matrix is:

   [1 1]

   [1 1]

MATHEMATICA

A269742 = Cases[Import["https://oeis.org/A269742/b269742.txt", "Table"], {_, _}][[All, 2]];

a[n_] := A269742[[n^2 - n + 1]];

Array[a, 40] (* Jean-François Alcover, Feb 24 2020 *)

CROSSREFS

Central coefficients of A269742.

Sequence in context: A201966 A121196 A251261 * A160465 A125446 A287838

Adjacent sequences:  A332726 A332727 A332728 * A332730 A332731 A332732

KEYWORD

nonn

AUTHOR

Andrew Howroyd, Feb 22 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 July 5 19:02 EDT 2020. Contains 335473 sequences. (Running on oeis4.)