cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-10 of 11 results. Next

A233302 Number of (2+1) X (n+1) 0..1 arrays x(i,j) with row sums sum{x(i,j), j=1..n+1} nondecreasing, and column sums sum{i^2*x(i,j), i=1..2+1} nondecreasing.

Original entry on oeis.org

15, 42, 105, 232, 475, 904, 1632, 2806, 4642, 7414, 11500, 17368, 25636, 37054, 52579, 73354, 100799, 136586, 182749, 241654, 316129, 409430, 525392, 668390, 843514, 1056524, 1314050, 1623542, 1993496, 2433398, 2953979, 3567152, 4286297, 5126192
Offset: 1

Views

Author

R. H. Hardin, Dec 07 2013

Keywords

Comments

Row 2 of A233301, row 3 of A267245.

Examples

			Some solutions for n=5:
..0..0..0..0..1..0....1..1..0..0..0..0....0..0..1..0..0..0....0..0..0..0..0..1
..0..0..0..0..0..1....0..0..1..1..1..1....0..0..0..0..0..1....0..1..1..1..1..1
..0..0..0..1..1..1....0..1..1..1..1..1....0..0..0..1..1..1....0..1..1..1..1..1
		

Crossrefs

Formula

Empirical: a(n) = 4*a(n-1) - 3*a(n-2) - 7*a(n-3) + 10*a(n-4) + 3*a(n-5) - 6*a(n-6) - 6*a(n-7) + 3*a(n-8) + 10*a(n-9) - 7*a(n-10) - 3*a(n-11) + 4*a(n-12) - a(n-13). - R. H. Hardin, Jan 17 2016.
Empirical g.f.: x*(15 - 18*x - 18*x^2 + 43*x^3 + 6*x^4 - 30*x^5 - 21*x^6 + 22*x^7 + 33*x^8 - 31*x^9 - 8*x^10 + 15*x^11 - 4*x^12) / ((1 - x)^8*(1 + x)^3*(1 + x + x^2)). - Colin Barker, Mar 19 2018

A233303 Number of (3+1)X(n+1) 0..1 arrays x(i,j) with row sums sum{x(i,j), j=1..n+1} nondecreasing, and column sums sum{i^2*x(i,j), i=1..3+1} nondecreasing.

Original entry on oeis.org

31, 141, 567, 1986, 6292, 18205, 48913, 123084, 292784, 662512, 1434508, 2985639, 5997455, 11666253, 22040149, 40541549, 72770415, 127706638, 219494579, 370035418, 612722058, 997726253, 1599424522, 2526675993, 3936943281
Offset: 1

Views

Author

R. H. Hardin, Dec 07 2013

Keywords

Comments

Row 3 of A233301, row 4 of A267245.

Examples

			Some solutions for n=5
..0..0..1..0..0..0....0..1..0..0..0..1....0..0..0..0..0..1....1..1..1..0..0..0
..1..0..0..1..0..0....0..0..0..1..1..1....1..0..1..0..0..1....0..0..0..1..1..1
..1..0..0..0..1..1....0..0..0..1..1..1....0..1..1..0..0..1....1..0..1..1..1..1
..0..1..1..1..1..1....0..0..1..1..1..1....0..0..0..1..1..1....0..1..1..1..1..1
		

A267240 Number of n X 3 binary arrays with row sums nondecreasing and columns lexicographically nondecreasing.

Original entry on oeis.org

4, 13, 42, 141, 486, 1685, 5804, 19769, 66544, 221581, 730918, 2391717, 7772610, 25110933, 80713016, 258280817, 823269116, 2615088973, 8281113730, 26150883901, 82375282494, 258893742933, 811984918692, 2541865829801, 7943330715176
Offset: 1

Views

Author

R. H. Hardin, Jan 12 2016

Keywords

Examples

			Some solutions for n=4:
..0..0..1....0..0..1....0..0..0....0..0..1....0..0..1....0..0..1....0..0..1
..0..1..0....0..1..0....0..1..1....0..0..1....0..1..0....0..0..1....1..1..0
..1..0..0....1..1..0....1..0..1....0..1..1....0..0..1....0..0..1....0..1..1
..1..1..0....1..1..1....0..1..1....0..1..1....0..0..1....1..1..0....1..0..1
		

Crossrefs

Column 3 of A267245.

Formula

Empirical: a(n) = 10*a(n-1) - 39*a(n-2) + 76*a(n-3) - 79*a(n-4) + 42*a(n-5) - 9*a(n-6).
Conjectures from Colin Barker, Jan 11 2019: (Start)
G.f.: x*(4 - 27*x + 68*x^2 - 76*x^3 + 42*x^4 - 9*x^5) / ((1 - x)^4*(1 - 3*x)^2).
a(n) = (24 + (31+3^(2+n))*n + 12*n^2 + 2*n^3) / 24.
(End)
Empirical recurrence verified (see link). - Robert Israel, Sep 08 2019

A267241 Number of nX4 binary arrays with row sums nondecreasing and columns lexicographically nondecreasing.

Original entry on oeis.org

5, 22, 105, 567, 3351, 20676, 129129, 804817, 4982759, 30629206, 187121865, 1137631979, 6891047527, 41628865000, 250987078681, 1511105743781, 9088662549303, 54625229882746, 328144877989145, 1970524978549951
Offset: 1

Views

Author

R. H. Hardin, Jan 12 2016

Keywords

Comments

Column 4 of A267245.

Examples

			Some solutions for n=4
..0..0..0..0....0..0..0..0....0..0..1..1....0..0..1..1....0..0..0..1
..0..0..0..0....0..0..0..1....0..0..1..1....0..1..0..1....0..1..1..0
..0..1..1..1....0..1..1..0....0..1..1..1....1..0..1..0....0..1..1..1
..1..0..1..1....0..1..1..0....1..0..1..1....1..0..1..0....0..1..1..1
		

Crossrefs

Cf. A267245.

Programs

  • Maple
    states:= select(proc(x) (x[1]=x[2] or x[5]=1) and (x[2]=x[3] or x[6]=1) and (x[3]=x[4] or x[7]=1) end proc, [seq(seq(seq(seq(seq(seq(seq([a,b,c,d,e,f,g],g=0..1),f=0..1),e=0..1),d=0..1),c=0..1),b=0..1),a=0..1)]):
    T:= Matrix(54,54,proc(i,j) local k;
      if add(states[j,k]-states[i,k],k=1..4) > 0 then return 0 fi;
      if states[j,5]>states[i,5] or states[j,6]>states[i,6] or states[j,7]>states[i,7] then return 0 fi;
      if states[i,1]>=states[i,2] and states[j,5]<> states[i,5] then return 0 fi;
      if states[i,2]>=states[i,3] and states[j,6]<> states[i,6] then return 0 fi;
      if states[i,3]>=states[i,4] and states[j,7]<> states[i,7] then return 0 fi;
    1
    end proc):
    U:= Vector(54,1):
    E[0]:= Vector(54): E[0][1]:= 1:
    for k from 1 to 25 do E[k]:= T . E[k-1] od:
    seq(U^%T . E[j], j=1..25); # Robert Israel, Sep 08 2019
  • Mathematica
    LinearRecurrence[{24, -246, 1420, -5121, 12084, -18944, 19536, -12720, 4736, -768}, {5, 22, 105, 567, 3351, 20676, 129129, 804817, 4982759, 30629206, 187121865}, 25] (* Jean-François Alcover, Oct 25 2022, after Robert Israel *)

Formula

Empirical: a(n) = 24*a(n-1) -246*a(n-2) +1420*a(n-3) -5121*a(n-4) +12084*a(n-5) -18944*a(n-6) +19536*a(n-7) -12720*a(n-8) +4736*a(n-9) -768*a(n-10).
Empirical formula verified (see link). - Robert Israel, Sep 08 2019

A267242 Number of nX5 binary arrays with row sums nondecreasing and columns lexicographically nondecreasing.

Original entry on oeis.org

6, 34, 232, 1986, 20040, 220235, 2499080, 28501471, 323067002, 3626695952, 40306404192, 443852375808, 4848323701804, 52590398731297, 567018802063680, 6081537709403509, 64929807220896558, 690446673537426382
Offset: 1

Views

Author

R. H. Hardin, Jan 12 2016

Keywords

Comments

Column 5 of A267245.

Examples

			Some solutions for n=4
..0..0..0..0..1....0..0..0..1..1....0..0..0..1..1....0..0..0..0..1
..0..0..0..1..0....0..1..1..0..0....0..1..1..0..0....0..0..0..1..0
..0..1..1..0..0....0..0..1..1..1....1..1..1..0..1....0..0..0..0..1
..1..0..1..1..1....1..0..1..0..1....1..1..1..1..0....0..1..1..1..0
		

Crossrefs

Cf. A267245.

Programs

  • Maple
    S[2]:= [[0,0,0],[0,0,1],[0,1,1],[1,0,1],[1,1,0],[1,1,1]]:
    for i from 3 to 5 do
      S[i]:= map(proc(t) [op(t[1..i-1]),t[i-1],op(t[i..-1]),0], [op(t[1..i-1]),t[i-1],op(t[i..-1]),1],
         [op(t[1..i-1]),1-t[i-1],op(t[i..-1]),1] end proc, S[i-1])
    od:
    states:= S[5]:
    T:= Matrix(162,162,proc(i,j) local k;
      if add(states[j,k]-states[i,k],k=1..5) > 0 then return 0 fi;
      for k from 6 to 9 do if states[j,k]>states[i,k] then return 0 fi od;
      for k from 1 to 4 do if states[i,k]>=states[i,k+1] and states[j,k+5]<>states[i,k+5] then return 0 fi od;
    1
    end proc):
    E:= Vector(162): E[1]:= 1:
    U[0]:= Vector[row](162,1):
    for k from 1 to 25 do U[k]:= U[k-1].T od:
    seq(U[j] . E, j=1..25); # Robert Israel, Sep 08 2019

Formula

Empirical: a(n) = 52*a(n-1) -1196*a(n-2) +16140*a(n-3) -142918*a(n-4) +879116*a(n-5) -3875668*a(n-6) +12442580*a(n-7) -29232481*a(n-8) +50015232*a(n-9) -61355336*a(n-10) +52355680*a(n-11) -29405200*a(n-12) +9744000*a(n-13) -1440000*a(n-14).
Empirical formula verified (see link). - Robert Israel, Sep 08 2019

A267243 Number of n X 6 binary arrays with row sums nondecreasing and columns lexicographically nondecreasing.

Original entry on oeis.org

7, 50, 475, 6292, 107015, 2093467, 43555569, 924051709, 19614050515, 413556580944, 8645774602327, 179276181587698, 3691120876565687, 75550095426967737, 1538986699132717645, 31229753343696948035
Offset: 1

Views

Author

R. H. Hardin, Jan 12 2016

Keywords

Comments

Column 6 of A267245.

Examples

			Some solutions for n=4:
  0 0 0 0 1 1   0 0 0 0 1 1   0 0 0 0 1 1   0 0 0 1 1 1
  0 0 0 1 0 1   0 0 1 1 0 0   0 0 1 1 0 0   0 1 1 0 0 1
  0 1 1 1 1 0   0 0 0 1 1 1   0 1 0 0 0 1   1 1 1 1 1 0
  0 0 1 1 1 1   0 1 0 1 0 1   1 1 0 1 0 1   1 0 1 1 1 1
		

Crossrefs

Cf. A267245.

Programs

  • Maple
    S[2]:= [[0,0,0],[0,0,1],[0,1,1],[1,0,1],[1,1,0],[1,1,1]]:
    for i from 3 to 6 do
      S[i]:= map(proc(t) [op(t[1..i-1]),t[i-1],op(t[i..-1]),0], [op(t[1..i-1]),t[i-1],op(t[i..-1]),1],
         [op(t[1..i-1]),1-t[i-1],op(t[i..-1]),1] end proc, S[i-1])
    od:
    states:= S[6]:
    T:= Matrix(486,486,proc(i,j) local k;
      if add(states[j,k]-states[i,k],k=1..6) > 0 then return 0 fi;
      for k from 7 to 11 do if states[j,k]>states[i,k] then return 0 fi od;
      for k from 1 to 5 do if states[i,k]>=states[i,k+1] and states[j,k+6]<>states[i,k+6] then return 0 fi od;
    1
    end proc):
    E:= Vector(486): E[1]:= 1:
    U[0]:= Vector[row](486,1):
    for k from 1 to 25 do U[k]:= U[k-1].T od:
    seq(U[j] . E, j=1..25); # Robert Israel, Sep 08 2019

Formula

Empirical: a(n) = 114*a(n-1) - 5915*a(n-2) + 186008*a(n-3) - 3982785*a(n-4) + 61835542*a(n-5) - 723657627*a(n-6) + 6549515604*a(n-7) - 46652032035*a(n-8) + 264676225246*a(n-9) - 1205477853945*a(n-10) + 4427867737616*a(n-11) - 13139368875011*a(n-12) + 31468929403866*a(n-13) - 60602488003009*a(n-14) + 93197329064964*a(n-15) - 113220771193368*a(n-16) + 106920682204032*a(n-17) - 76630180181904*a(n-18) + 40173465734208*a(n-19) - 14497964755200*a(n-20) + 3213273369600*a(n-21) - 329204736000*a(n-22).
Empirical formula verified (see link). - Robert Israel, Sep 08 2019

A267244 Number of n X 7 binary arrays with row sums nondecreasing and columns lexicographically nondecreasing.

Original entry on oeis.org

8, 70, 904, 18205, 516084, 17892539, 683027146, 27044976947, 1079112886476, 42860145907558, 1687239907979286, 65777529883058423, 2540922972496976428, 97351678797063744735, 3703224984260808730288, 139993814565092144904305
Offset: 1

Views

Author

R. H. Hardin, Jan 12 2016

Keywords

Comments

Column 7 of A267245.

Examples

			Some solutions for n=4:
  0 0 0 0 0 0 0    0 0 0 0 0 1 1    0 0 0 0 0 0 1
  0 0 0 0 0 0 0    0 0 0 0 1 0 1    0 0 0 1 1 1 0
  0 0 0 0 1 1 1    0 0 1 1 0 0 0    0 0 1 0 1 1 0
  0 0 1 1 0 1 1    0 1 1 1 1 0 0    0 0 1 1 0 1 0
		

Crossrefs

Cf. A267245.

Programs

  • Maple
    S[2]:= [[0,0,0],[0,0,1],[0,1,1],[1,0,1],[1,1,0],[1,1,1]]:
    for i from 3 to 7 do
      S[i]:= map(proc(t) [op(t[1..i-1]),t[i-1],op(t[i..-1]),0], [op(t[1..i-1]),t[i-1],op(t[i..-1]),1],
         [op(t[1..i-1]),1-t[i-1],op(t[i..-1]),1] end proc, S[i-1])
    od:
    states:= S[7]:
    T:= Matrix(1458,1458,proc(i,j) local k;
      if add(states[j,k]-states[i,k],k=1..7) > 0 then return 0 fi;
      for k from 8 to 13 do if states[j,k]>states[i,k] then return 0 fi od;
      for k from 1 to 6 do if states[i,k]>=states[i,k+1] and states[j,k+7]<>states[i,k+7] then return 0 fi od;
    1
    end proc):
    E:= Vector(1458): E[1]:= 1:
    U[0]:= Vector[row](1458,1):
    for k from 1 to 32 do U[k]:= U[k-1].T od:
    seq(U[j] . E, j=1..32);  # Robert Israel, Sep 08 2019

Formula

Empirical: a(n) = 236*a(n-1) - 25680*a(n-2) + 1717504*a(n-3) - 79417394*a(n-4) + 2707798440*a(n-5) - 70899406188*a(n-6) + 1465896913824*a(n-7) - 24421757248431*a(n-8) + 332861244138564*a(n-9) - 3755300016546300*a(n-10) + 35390628699049728*a(n-11) - 280610566308801516*a(n-12) + 1882413463252467120*a(n-13) - 10729331312513919192*a(n-14) + 52123544280277991616*a(n-15) - 216277785263000273775*a(n-16) + 767370439659990868020*a(n-17) - 2328674591889971376488*a(n-18) + 6039623808173911907968*a(n-19) - 13364805995823788545362*a(n-20) + 25161918805489259088488*a(n-21) - 40140151907739595227388*a(n-22) + 53955000634729356546720*a(n-23) - 60650423670523051920321*a(n-24) + 56445409553303282568732*a(n-25) - 42910761548685014780364*a(n-26) + 26160176586524646234240*a(n-27) - 12460398044348337274800*a(n-28) + 4460624272170497592000*a(n-29) - 1127355192728480520000*a(n-30) + 179146175950526400000*a(n-31) - 13449500030736000000*a(n-32).
Empirical formula verified (see link). - Robert Israel, Sep 08 2019

A267239 Number of n X n binary arrays with row sums nondecreasing and columns lexicographically nondecreasing.

Original entry on oeis.org

2, 7, 42, 567, 20040, 2093467, 683027146, 723576702570, 2549735632656528, 30465608408449993885, 1250919952257037350168062, 178764247753852768666003981113, 89752660973687899647122735126286078
Offset: 1

Views

Author

R. H. Hardin, Jan 12 2016

Keywords

Comments

Diagonal of A267245.

Examples

			Some solutions for n=4
..0..0..0..1....0..0..0..1....0..0..1..1....0..0..0..1....0..0..0..1
..0..1..1..0....0..0..0..1....0..1..0..1....0..0..1..1....0..0..1..1
..1..0..1..0....0..0..1..1....1..1..0..0....0..1..0..1....1..1..1..0
..1..1..1..1....1..1..1..0....1..1..0..0....1..1..1..0....1..1..0..1
		

Crossrefs

Cf. A267245.

A267248 Number of 5Xn binary arrays with row sums nondecreasing and columns lexicographically nondecreasing.

Original entry on oeis.org

6, 63, 486, 3351, 20040, 107015, 516084, 2278687, 9303052, 35428544, 126753732, 428651446, 1377310514, 4223642819, 12409437728, 35050866249, 95459908872, 251341796912, 641282264972, 1588863292072
Offset: 1

Views

Author

R. H. Hardin, Jan 12 2016

Keywords

Comments

Row 5 of A267245.

Examples

			Some solutions for n=4
..0..0..0..0....0..0..0..1....0..0..0..0....0..0..0..0....0..0..0..0
..0..0..1..1....0..0..0..1....0..0..0..1....0..0..0..1....0..0..0..0
..1..1..0..0....0..0..1..0....0..1..1..0....0..0..1..0....0..0..0..1
..1..1..0..1....1..1..0..1....1..0..1..1....1..1..0..1....0..0..1..1
..1..1..1..1....0..1..1..1....0..1..1..1....0..1..1..1....1..1..1..1
		

Crossrefs

Cf. A267245.

A267249 Number of 6Xn binary arrays with row sums nondecreasing and columns lexicographically nondecreasing.

Original entry on oeis.org

7, 127, 1685, 20676, 220235, 2093467, 17892539, 139164323, 993947185, 6572368601, 40512935649, 234192144667, 1276154088792, 6584891361478, 32302298031855, 151176059240006
Offset: 1

Views

Author

R. H. Hardin, Jan 12 2016

Keywords

Comments

Row 6 of A267245.

Examples

			Some solutions for n=4
..0..0..0..1....0..0..0..1....0..0..1..1....0..0..0..1....0..0..0..1
..0..0..1..0....1..1..1..0....1..1..0..0....0..0..1..1....0..0..1..0
..0..1..0..0....1..1..1..0....1..1..0..0....0..1..1..0....0..1..1..0
..1..1..0..0....0..1..1..1....0..1..0..1....1..1..1..0....1..1..0..0
..0..1..1..0....1..0..1..1....1..1..0..0....1..1..0..1....0..1..1..1
..1..1..0..0....0..1..1..1....0..1..1..0....1..1..1..1....1..1..1..1
		

Crossrefs

Cf. A267245.
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