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 10 results.

A250657 Number of (3+1)X(n+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.

Original entry on oeis.org

39, 70, 109, 156, 211, 274, 345, 424, 511, 606, 709, 820, 939, 1066, 1201, 1344, 1495, 1654, 1821, 1996, 2179, 2370, 2569, 2776, 2991, 3214, 3445, 3684, 3931, 4186, 4449, 4720, 4999, 5286, 5581, 5884, 6195, 6514, 6841, 7176, 7519, 7870, 8229, 8596, 8971
Offset: 1

Views

Author

R. H. Hardin, Nov 26 2014

Keywords

Comments

Row 3 of A250656

Examples

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

Formula

Empirical: a(n) = 4*n^2 + 19*n + 16

A250653 Number of (n+1)X(5+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.

Original entry on oeis.org

49, 103, 211, 427, 859, 1723, 3451, 6907, 13819, 27643, 55291, 110587, 221179, 442363, 884731, 1769467, 3538939, 7077883, 14155771, 28311547, 56623099, 113246203, 226492411, 452984827, 905969659, 1811939323, 3623878651
Offset: 1

Views

Author

R. H. Hardin, Nov 26 2014

Keywords

Comments

Column 5 of A250656.
Since one edge length of the array is fixed, and the constraint is a Markov-type correlation between fixed-width lengths of the other edge, the generating function is computable by the usual transfer matrix method and therefore a rational polynomial. That predicts that there is a linear recurrence. - R. J. Mathar, May 25 2018

Examples

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

Crossrefs

Cf. A304387.

Formula

Empirical: a(n) = 3*a(n-1) - 2*a(n-2); also a(n) = 2^(n-1)*25 + (5*2^(n-1)-1)*5 + 2^(n+1).
It appears that a(n) = 27*2^n-5, which would make this coincide with A304387. - N. J. A. Sloane, May 13 2018

A250652 Number of (n+1)X(n+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.

Original entry on oeis.org

9, 34, 109, 316, 859, 2234, 5625, 13816, 33271, 78838, 184309, 425972, 974835, 2211826, 4980721, 11141104, 24772591, 54788078, 120586221, 264241132, 576716779, 1254096874, 2717908969, 5872025576, 12650020839, 27179089894
Offset: 1

Views

Author

R. H. Hardin, Nov 26 2014

Keywords

Comments

Diagonal of A250656

Examples

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

A250654 Number of (n+1) X (6+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.

Original entry on oeis.org

64, 134, 274, 554, 1114, 2234, 4474, 8954, 17914, 35834, 71674, 143354, 286714, 573434, 1146874, 2293754, 4587514, 9175034, 18350074, 36700154, 73400314, 146800634, 293601274, 587202554, 1174405114, 2348810234, 4697620474
Offset: 1

Views

Author

R. H. Hardin, Nov 26 2014

Keywords

Examples

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

Crossrefs

Column 6 of A250656.

Formula

Empirical: a(n) = 3*a(n-1) - 2*a(n-2); also a(n) = 2^(n-1)*36 + (5*2^(n-1)-1)*6 + 2^(n+1).
Empirical g.f.: 2*x*(32 - 29*x) / ((1 - x)*(1 - 2*x)). - Colin Barker, Nov 15 2018

A250655 Number of (n+1) X (7+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.

Original entry on oeis.org

81, 169, 345, 697, 1401, 2809, 5625, 11257, 22521, 45049, 90105, 180217, 360441, 720889, 1441785, 2883577, 5767161, 11534329, 23068665, 46137337, 92274681, 184549369, 369098745, 738197497, 1476395001, 2952790009, 5905580025
Offset: 1

Views

Author

R. H. Hardin, Nov 26 2014

Keywords

Examples

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

Crossrefs

Column 7 of A250656.

Formula

Empirical: a(n) = 3*a(n-1) - 2*a(n-2); also a(n) = 2^(n-1)*49 + (5*2^(n-1)-1)*7 +2^(n+1).
Empirical g.f.: x*(81 - 74*x) / ((1 - x)*(1 - 2*x)). - Colin Barker, Nov 15 2018

A250658 Number of (4+1) X (n+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.

Original entry on oeis.org

79, 142, 221, 316, 427, 554, 697, 856, 1031, 1222, 1429, 1652, 1891, 2146, 2417, 2704, 3007, 3326, 3661, 4012, 4379, 4762, 5161, 5576, 6007, 6454, 6917, 7396, 7891, 8402, 8929, 9472, 10031, 10606, 11197, 11804, 12427, 13066, 13721, 14392, 15079, 15782
Offset: 1

Views

Author

R. H. Hardin, Nov 26 2014

Keywords

Examples

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

Crossrefs

Row 4 of A250656.

Formula

Empirical: a(n) = 8*n^2 + 39*n + 32.
Conjectures from Colin Barker, Nov 15 2018: (Start)
G.f.: x*(79 - 95*x + 32*x^2) / (1 - x)^3.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>3.
(End)

A250659 Number of (5+1) X (n+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.

Original entry on oeis.org

159, 286, 445, 636, 859, 1114, 1401, 1720, 2071, 2454, 2869, 3316, 3795, 4306, 4849, 5424, 6031, 6670, 7341, 8044, 8779, 9546, 10345, 11176, 12039, 12934, 13861, 14820, 15811, 16834, 17889, 18976, 20095, 21246, 22429, 23644, 24891, 26170, 27481, 28824
Offset: 1

Views

Author

R. H. Hardin, Nov 26 2014

Keywords

Examples

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

Crossrefs

Row 5 of A250656.

Formula

Empirical: a(n) = 16*n^2 + 79*n + 64.
Conjectures from Colin Barker, Nov 15 2018: (Start)
G.f.: x*(159 - 191*x + 64*x^2) / (1 - x)^3.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>3.
(End)

A250660 Number of (6+1) X (n+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.

Original entry on oeis.org

319, 574, 893, 1276, 1723, 2234, 2809, 3448, 4151, 4918, 5749, 6644, 7603, 8626, 9713, 10864, 12079, 13358, 14701, 16108, 17579, 19114, 20713, 22376, 24103, 25894, 27749, 29668, 31651, 33698, 35809, 37984, 40223, 42526, 44893, 47324, 49819, 52378, 55001
Offset: 1

Views

Author

R. H. Hardin, Nov 26 2014

Keywords

Examples

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

Crossrefs

Row 6 of A250656.

Formula

Empirical: a(n) = 32*n^2 + 159*n + 128.
Conjectures from Colin Barker, Nov 15 2018: (Start)
G.f.: x*(319 - 383*x + 128*x^2) / (1 - x)^3.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>3.
(End)

A250661 Number of (7+1) X (n+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.

Original entry on oeis.org

639, 1150, 1789, 2556, 3451, 4474, 5625, 6904, 8311, 9846, 11509, 13300, 15219, 17266, 19441, 21744, 24175, 26734, 29421, 32236, 35179, 38250, 41449, 44776, 48231, 51814, 55525, 59364, 63331, 67426, 71649, 76000, 80479, 85086, 89821, 94684, 99675
Offset: 1

Views

Author

R. H. Hardin, Nov 26 2014

Keywords

Examples

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

Crossrefs

Row 7 of A250656.

Formula

Empirical: a(n) = 64*n^2 + 319*n + 256.
Conjectures from Colin Barker, Nov 16 2018: (Start)
G.f.: x*(639 - 767*x + 256*x^2) / (1 - x)^3.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>3.
(End)

A303273 Array T(n,k) = binomial(n, 2) + k*n + 1 read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 1, 3, 4, 4, 1, 4, 6, 7, 7, 1, 5, 8, 10, 11, 11, 1, 6, 10, 13, 15, 16, 16, 1, 7, 12, 16, 19, 21, 22, 22, 1, 8, 14, 19, 23, 26, 28, 29, 29, 1, 9, 16, 22, 27, 31, 34, 36, 37, 37, 1, 10, 18, 25, 31, 36, 40, 43, 45, 46, 46, 1, 11, 20, 28, 35, 41
Offset: 0

Views

Author

Keywords

Comments

Columns are linear recurrence sequences with signature (3,-3,1).
8*T(n,k) + A166147(k-1) are squares.
Columns k are binomial transforms of [1, k, 1, 0, 0, 0, ...].
Antidiagonals sums yield A116731.

Examples

			The array T(n,k) begins
1    1    1    1    1    1    1    1    1    1    1    1    1  ...  A000012
1    2    3    4    5    6    7    8    9   10   11   12   13  ...  A000027
2    4    6    8   10   12   14   16   18   20   22   24   26  ...  A005843
4    7   10   13   16   19   22   25   28   31   34   37   40  ...  A016777
7   11   15   19   23   27   31   35   39   43   47   51   55  ...  A004767
11  16   21   26   31   36   41   46   51   56   61   66   71  ...  A016861
16  22   28   34   40   46   52   58   64   70   76   82   88  ...  A016957
22  29   36   43   50   57   64   71   78   85   92   99  106  ...  A016993
29  37   45   53   61   69   77   85   93  101  109  117  125  ...  A004770
37  46   55   64   73   82   91  100  109  118  127  136  145  ...  A017173
46  56   66   76   86   96  106  116  126  136  146  156  166  ...  A017341
56  67   78   89  100  111  122  133  144  155  166  177  188  ...  A017401
67  79   91  103  115  127  139  151  163  175  187  199  211  ...  A017605
79  92  105  118  131  144  157  170  183  196  209  222  235  ...  A190991
...
The inverse binomial transforms of the columns are
1    1    1    1    1    1    1    1    1    1    1    1    1  ...
0    1    2    3    4    5    6    7    8    9   10   11   12  ...
1    1    1    1    1    1    1    1    1    1    1    1    1  ...
0    0    0    0    0    0    0    0    0    0    0    0    0  ...
0    0    0    0    0    0    0    0    0    0    0    0    0  ...
0    0    0    0    0    0    0    0    0    0    0    0    0  ...
...
T(k,n-k) = A087401(n,k) + 1 as triangle
1
1   1
1   2   2
1   3   4   4
1   4   6   7   7
1   5   8  10  11  11
1   6  10  13  15  16  16
1   7  12  16  19  21  22  22
1   8  14  19  23  26  28  29  29
1   9  16  22  27  31  34  36  37  37
1  10  18  25  31  36  40  43  45  46  46
...
		

References

  • R. L. Graham, D. E. Knuth and O. Patashnik, Concrete Mathematics: A Foundation for Computer Science, Addison-Wesley, 1994.

Crossrefs

Programs

  • Maple
    T := (n, k) -> binomial(n, 2) + k*n + 1;
    for n from 0 to 20 do seq(T(n, k), k = 0 .. 20) od;
  • Mathematica
    Table[With[{n = m - k}, Binomial[n, 2] + k n + 1], {m, 0, 11}, {k, m, 0, -1}] // Flatten (* Michael De Vlieger, Apr 21 2018 *)
  • Maxima
    T(n, k) := binomial(n, 2)+ k*n + 1$
    for n:0 thru 20 do
        print(makelist(T(n, k), k, 0, 20));
    
  • PARI
    T(n,k) = binomial(n, 2) + k*n + 1;
    tabl(nn) = for (n=0, nn, for (k=0, nn, print1(T(n, k), ", ")); print); \\ Michel Marcus, May 17 2018

Formula

G.f.: (3*x^2*y - 3*x*y + y - 2*x^2 + 2*x - 1)/((x - 1)^3*(y - 1)^2).
E.g.f.: (1/2)*(2*x*y + x^2 + 2)*exp(y + x).
T(n,k) = 3*T(n-1,k) - 3*T(n-2,k) + T(n-3,k), with T(0,k) = 1, T(1,k) = k + 1 and T(2,k) = 2*k + 2.
T(n,k) = T(n-1,k) + n + k - 1.
T(n,k) = T(n,k-1) + n, with T(n,0) = 1.
T(n,0) = A152947(n+1).
T(n,1) = A000124(n).
T(n,2) = A000217(n).
T(n,3) = A034856(n+1).
T(n,4) = A052905(n).
T(n,5) = A051936(n+4).
T(n,6) = A246172(n+1).
T(n,7) = A302537(n).
T(n,8) = A056121(n+1) + 1.
T(n,9) = A056126(n+1) + 1.
T(n,10) = A051942(n+10) + 1, n > 0.
T(n,11) = A101859(n) + 1.
T(n,12) = A132754(n+1) + 1.
T(n,13) = A132755(n+1) + 1.
T(n,14) = A132756(n+1) + 1.
T(n,15) = A132757(n+1) + 1.
T(n,16) = A132758(n+1) + 1.
T(n,17) = A212427(n+1) + 1.
T(n,18) = A212428(n+1) + 1.
T(n,n) = A143689(n) = A300192(n,2).
T(n,n+1) = A104249(n).
T(n,n+2) = T(n+1,n) = A005448(n+1).
T(n,n+3) = A000326(n+1).
T(n,n+4) = A095794(n+1).
T(n,n+5) = A133694(n+1).
T(n+2,n) = A005449(n+1).
T(n+3,n) = A115067(n+2).
T(n+4,n) = A133694(n+2).
T(2*n,n) = A054556(n+1).
T(2*n,n+1) = A054567(n+1).
T(2*n,n+2) = A033951(n).
T(2*n,n+3) = A001107(n+1).
T(2*n,n+4) = A186353(4*n+1) (conjectured).
T(2*n,n+5) = A184103(8*n+1) (conjectured).
T(2*n,n+6) = A250657(n-1) = A250656(3,n-1), n > 1.
T(n,2*n) = A140066(n+1).
T(n+1,2*n) = A005891(n).
T(n+2,2*n) = A249013(5*n+4) (conjectured).
T(n+3,2*n) = A186384(5*n+3) = A186386(5*n+3) (conjectured).
T(2*n,2*n) = A143689(2*n).
T(2*n+1,2*n+1) = A143689(2*n+1) (= A030503(3*n+3) (conjectured)).
T(2*n,2*n+1) = A104249(2*n) = A093918(2*n+2) = A131355(4*n+1) (= A030503(3*n+5) (conjectured)).
T(2*n+1,2*n) = A085473(n).
a(n+1,5*n+1)=A051865(n+1) + 1.
a(n,2*n+1) = A116668(n).
a(2*n+1,n) = A054569(n+1).
T(3*n,n) = A025742(3*n-1), n > 1 (conjectured).
T(n,3*n) = A140063(n+1).
T(n+1,3*n) = A069099(n+1).
T(n,4*n) = A276819(n).
T(4*n,n) = A154106(n-1), n > 0.
T(2^n,2) = A028401(n+2).
T(1,n)*T(n,1) = A006000(n).
T(n*(n+1),n) = A211905(n+1), n > 0 (conjectured).
T(n*(n+1)+1,n) = A294259(n+1).
T(n,n^2+1) = A081423(n).
T(n,A000217(n)) = A158842(n), n > 0.
T(n,A152947(n+1)) = A060354(n+1).
floor(T(n,n/2)) = A267682(n) (conjectured).
floor(T(n,n/3)) = A025742(n-1), n > 0 (conjectured).
floor(T(n,n/4)) = A263807(n-1), n > 0 (conjectured).
ceiling(T(n,2^n)/n) = A134522(n), n > 0 (conjectured).
ceiling(T(n,n/2+n)/n) = A051755(n+1) (conjectured).
floor(T(n,n)/n) = A133223(n), n > 0 (conjectured).
ceiling(T(n,n)/n) = A007494(n), n > 0.
ceiling(T(n,n^2)/n) = A171769(n), n > 0.
ceiling(T(2*n,n^2)/n) = A046092(n), n > 0.
ceiling(T(2*n,2^n)/n) = A131520(n+2), n > 0.
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