login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A180985 Array T(n,k) = number of n X k binary matrices with rows and columns in lexicographically nondecreasing order. 8

%I #27 May 05 2022 04:44:51

%S 2,3,3,4,7,4,5,14,14,5,6,25,45,25,6,7,41,130,130,41,7,8,63,336,650,

%T 336,63,8,9,92,785,2942,2942,785,92,9,10,129,1682,11819,24520,11819,

%U 1682,129,10,11,175,3351,42305,183010,183010,42305,3351,175,11,12,231,6280,136564

%N Array T(n,k) = number of n X k binary matrices with rows and columns in lexicographically nondecreasing order.

%C Differs from "number of inequivalent {0,1}-matrices of size n X k, modulo permutations of rows and columns", A241956, starting at T(2, 3) = 14 while A241956(2, 3) = 13. - _M. F. Hasler_, Apr 27 2022

%H R. H. Hardin, <a href="/A180985/b180985.txt">Table of n, a(n) for n=1..311</a>

%H <a href="/index/Mat#inequiv">Index to OEIS entries related to inequivalent matrices modulo permutation of row and columns</a>.

%F T(n,k) = T(k,n). T(1,k) = k+1. T(2,k) = A004006(k+1). T(3,k) = A184138(k). - _M. F. Hasler_, Apr 27 2022

%e Table starts:

%e ..2...3.....4.......5.........6...........7.............8................9

%e ..3...7....14......25........41..........63............92..............129

%e ..4..14....45.....130.......336.........785..........1682.............3351

%e ..5..25...130.....650......2942.......11819.........42305...........136564

%e ..6..41...336....2942.....24520......183010.......1202234..........6979061

%e ..7..63...785...11819....183010.....2625117......33345183........371484319

%e ..8..92..1682...42305...1202234....33345183.....836488618......18470742266

%e ..9.129..3351..136564...6979061...371484319...18470742266.....818230288201

%e .10.175..6280..402910..36211867..3651371519..358194085968...31887670171373

%e .11.231.11176.1099694.170079565.32017940222.6148026957098.1096628939510047

%e .

%e All solutions for 3 X 3:

%e ..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0

%e ..0..0..0....0..0..0....0..0..1....0..0..1....0..0..1....0..1..1....0..0..0

%e ..0..0..1....0..1..1....0..1..0....0..0..1....0..1..1....0..1..1....1..1..1

%e .

%e ..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..1....0..0..1

%e ..0..0..1....0..1..1....0..0..1....0..1..1....0..1..1....0..1..0....0..1..0

%e ..1..1..0....1..0..0....1..1..1....1..0..1....1..1..1....0..1..0....0..1..1

%e .

%e ..0..0..1....0..0..1....0..0..1....0..0..1....0..0..1....0..0..1....0..0..1

%e ..0..0..1....0..0..1....0..0..1....0..1..1....0..1..0....0..1..0....0..1..0

%e ..0..1..0....0..0..1....0..1..1....0..1..1....1..0..0....1..1..0....1..0..1

%e .

%e ..0..0..1....0..0..1....0..0..1....0..0..1....0..0..1....0..0..1....0..0..1

%e ..0..1..0....0..0..1....0..1..1....0..1..1....0..0..1....0..1..1....0..1..1

%e ..1..1..1....1..1..0....1..0..0....1..1..0....1..1..1....1..0..1....1..1..1

%e .

%e ..0..0..0....0..0..1....0..0..1....0..0..1....0..1..1....0..1..1....0..1..1

%e ..1..1..1....1..1..0....1..1..0....1..1..1....0..1..1....0..1..1....0..1..1

%e ..1..1..1....1..1..0....1..1..1....1..1..1....0..1..1....1..0..0....1..0..1

%e ...

%e ..0..1..1....0..1..1....0..1..1....0..1..1....0..1..1....0..1..1....0..1..1

%e ..0..1..1....1..0..0....1..0..0....1..0..0....1..0..1....1..0..1....1..0..1

%e ..1..1..1....1..0..0....1..0..1....1..1..1....1..1..0....1..0..1....1..1..1

%e .

%e ..0..1..1....1..1..1

%e ..1..1..1....1..1..1

%e ..1..1..1....1..1..1

%o (PARI) A180985(h,w,cnt=0)={ local(A=matrix(h,w), z(r,c)=!while(r<h, A[r++,c]==A[r,c-1]||return)); while(cnt++, for(r=1,h, for(c=1,w, A[r,c] && next; A[r,c]=1; while(c>1 && z(r,c), c--); while(c>1, A[r,c--]=0); while(r>1, A[r--,]=A[r+1,]); next(3))); break); cnt} \\ _M. F. Hasler_, Apr 27 2022

%Y Cf. A089006 (diagonal).

%Y Cf. A004006 (row & column 2), A184138 (row & column 3).

%Y Cf. A241956 (similar but different).

%K nonn,tabl

%O 1,1

%A _R. H. Hardin_, Sep 30 2010

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 25 01:35 EDT 2024. Contains 371964 sequences. (Running on oeis4.)