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.

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A211422 Number of ordered triples (w,x,y) with all terms in {-n,...,0,...,n} and w^2 + x*y = 0.

Original entry on oeis.org

1, 9, 17, 25, 41, 49, 57, 65, 81, 105, 113, 121, 137, 145, 153, 161, 193, 201, 225, 233, 249, 257, 265, 273, 289, 329, 337, 361, 377, 385, 393, 401, 433, 441, 449, 457, 505, 513, 521, 529, 545, 553, 561, 569, 585, 609, 617, 625, 657, 713, 753, 761
Offset: 0

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Author

Clark Kimberling, Apr 10 2012

Keywords

Comments

Suppose that S={-n,...,0,...,n} and that f(w,x,y,n) is a function, where w,x,y are in S. The number of ordered triples (w,x,y) satisfying f(w,x,y,n)=0, regarded as a function of n, is a sequence t of nonnegative integers. Sequences such as t/4 may also be integer sequences for all except certain initial values of n. In the following guide, such sequences are indicated in the related sequences column and may be included in the corresponding Mathematica programs.
...
sequence... f(w,x,y,n) ..... related sequences
A211415 ... w^2+x*y-1 ...... t+2, t/4, (t/4-1)/4
A211422 ... w^2+x*y ........ (t-1)/8, A120486
A211423 ... w^2+2x*y ....... (t-1)/4
A211424 ... w^2+3x*y ....... (t-1)/4
A211425 ... w^2+4x*y ....... (t-1)/4
A211426 ... 2w^2+x*y ....... (t-1)/4
A211427 ... 3w^2+x*y ....... (t-1)/4
A211428 ... 2w^2+3x*y ...... (t-1)/4
A211429 ... w^3+x*y ........ (t-1)/4
A211430 ... w^2+x+y ........ (t-1)/2
A211431 ... w^3+(x+y)^2 .... (t-1)/2
A211432 ... w^2-x^2-y^2 .... (t-1)/8
A003215 ... w+x+y .......... (t-1)/2, A045943
A202253 ... w+2x+3y ........ (t-1)/2, A143978
A211433 ... w+2x+4y ........ (t-1)/2
A211434 ... w+2x+5y ........ (t-1)/4
A211435 ... w+4x+5y ........ (t-1)/2
A211436 ... 2w+3x+4y ....... (t-1)/2
A211435 ... 2w+3x+5y ....... (t-1)/2
A211438 ... w+2x+2y ....... (t-1)/2, A118277
A001844 ... w+x+2y ......... (t-1)/4, A000217
A211439 ... w+3x+3y ........ (t-1)/2
A211440 ... 2w+3x+3y ....... (t-1)/2
A028896 ... w+x+y-1 ........ t/6, A000217
A211441 ... w+x+y-2 ........ t/3, A028387
A182074 ... w^2+x*y-n ...... t/4, A028387
A000384 ... w+x+y-n
A000217 ... w+x+y-2n
A211437 ... w*x*y-n ........ t/4, A007425
A211480 ... w+2x+3y-1
A211481 ... w+2x+3y-n
A211482 ... w*x+w*y+x*y-w*x*y
A211483 ... (n+w)^2-x-y
A182112 ... (n+w)^2-x-y-w
...
For the following sequences, S={1,...,n}, rather than
{-n,...,0,...n}. If f(w,x,y,n) is linear in w,x,y,n, then the sequence is a linear recurrence sequence.
A132188 ... w^2-x*y
A211506 ... w^2-x*y-n
A211507 ... w^2-x*y+n
A211508 ... w^2+x*y-n
A211509 ... w^2+x*y-2n
A211510 ... w^2-x*y+2n
A211511 ... w^2-2x*y ....... t/2
A211512 ... w^2-3x*y ....... t/2
A211513 ... 2w^2-x*y ....... t/2
A211514 ... 3w^2-x*y ....... t/2
A211515 ... w^3-x*y
A211516 ... w^2-x-y
A211517 ... w^3-(x+y)^2
A063468 ... w^2-x^2-y^2 .... t/2
A000217 ... w+x-y
A001399 ... w-2x-3y
A211519 ... w-2x+3y
A008810 ... w+2x-3y
A001399 ... w-2x-3y
A008642 ... w-2x-4y
A211520 ... w-2x+4y
A211521 ... w+2x-4y
A000115 ... w-2x-5y
A211522 ... w-2x+5y
A211523 ... w+2x-5y
A211524 ... w-3x-5y
A211533 ... w-3x+5y
A211523 ... w+3x-5y
A211535 ... w-4x-5y
A211536 ... w-4x+5y
A008812 ... w+4x-5y
A055998 ... w+x+y-2n
A074148 ... 2w+x+y-2n
A211538 ... 2w+2x+y-2n
A211539 ... 2w+2x-y-2n
A211540 ... 2w-3x-4y
A211541 ... 2w-3x+4y
A211542 ... 2w+3x-4y
A211543 ... 2w-3x-5y
A211544 ... 2w-3x+5y
A008812 ... 2w+3x-5y
A008805 ... w-2x-2y (repeated triangular numbers)
A001318 ... w-2x+2y
A000982 ... w+x-2y
A211534 ... w-3x-3y
A211546 ... w-3x+3y (triply repeated triangular numbers)
A211547 ... 2w-3x-3y (triply repeated squares)
A082667 ... 2w-3x+3y
A055998 ... w-x-y+2
A001399 ... w-2x-3y+1
A108579 ... w-2x-3y+n
...
Next, S={-n,...-1,1,...,n}, and the sequence counts the cases (w,x,y) satisfying the indicated inequality. If f(w,x,y,n) is linear in w,x,y,n, then the sequence is a linear recurrence sequence.
A211545 ... w+x+y>0; recurrence degree: 4
A211612 ... w+x+y>=0
A211613 ... w+x+y>1
A211614 ... w+x+y>2
A211615 ... |w+x+y|<=1
A211616 ... |w+x+y|<=2
A211617 ... 2w+x+y>0; recurrence degree: 5
A211618 ... 2w+x+y>1
A211619 ... 2w+x+y>2
A211620 ... |2w+x+y|<=1
A211621 ... w+2x+3y>0
A211622 ... w+2x+3y>1
A211623 ... |w+2x+3y|<=1
A211624 ... w+2x+2y>0; recurrence degree: 6
A211625 ... w+3x+3y>0; recurrence degree: 8
A211626 ... w+4x+4y>0; recurrence degree: 10
A211627 ... w+5x+5y>0; recurrence degree: 12
A211628 ... 3w+x+y>0; recurrence degree: 6
A211629 ... 4w+x+y>0; recurrence degree: 7
A211630 ... 5w+x+y>0; recurrence degree: 8
A211631 ... w^2>x^2+y^2; all terms divisible by 8
A211632 ... 2w^2>x^2+y^2; all terms divisible by 8
A211633 ... w^2>2x^2+2y^2; all terms divisible by 8
...
Next, S={1,...,n}, and the sequence counts the cases (w,x,y) satisfying the indicated relation.
A211634 ... w^2<=x^2+y^2
A211635 ... w^2A211790
A211636 ... w^2>=x^2+y^2
A211637 ... w^2>x^2+y^2
A211638 ... w^2+x^2+y^2
A211639 ... w^2+x^2+y^2<=n
A211640 ... w^2+x^2+y^2>n
A211641 ... w^2+x^2+y^2>=n
A211642 ... w^2+x^2+y^2<2n
A211643 ... w^2+x^2+y^2<=2n
A211644 ... w^2+x^2+y^2>2n
A211645 ... w^2+x^2+y^2>=2n
A211646 ... w^2+x^2+y^2<3n
A211647 ... w^2+x^2+y^2<=3n
A063691 ... w^2+x^2+y^2=n
A211649 ... w^2+x^2+y^2=2n
A211648 ... w^2+x^2+y^2=3n
A211650 ... w^3A211790
A211651 ... w^3>x^3+y^3; see Comments at A211790
A211652 ... w^4A211790
A211653 ... w^4>x^4+y^4; see Comments at A211790

Examples

			a(1) counts these 9 triples: (-1,-1,1), (-1, 1,-1), (0, -1, 0), (0, 0, -1), (0,0,0), (0,0,1), (0,1,0), (1,-1,1), (1,1,-1).
		

Crossrefs

Cf. A120486.

Programs

  • Mathematica
    t[n_] := t[n] = Flatten[Table[w^2 + x*y, {w, -n, n}, {x, -n, n}, {y, -n, n}]]
    c[n_] := Count[t[n], 0]
    t = Table[c[n], {n, 0, 70}] (* A211422 *)
    (t - 1)/8                   (* A120486 *)

A182260 Number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w

Original entry on oeis.org

0, 3, 11, 28, 56, 99, 159, 240, 344, 475, 635, 828, 1056, 1323, 1631, 1984, 2384, 2835, 3339, 3900, 4520, 5203, 5951, 6768, 7656, 8619, 9659, 10780, 11984, 13275, 14655, 16128, 17696, 19363, 21131, 23004, 24984, 27075, 29279, 31600, 34040
Offset: 1

Author

Clark Kimberling, Apr 22 2012

Keywords

Comments

Also the number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w>x+y.
A182260(n)+A055232(n)=3^(n-1).
A182260 is row 1 of A211802 and also row 1 of A182259; see A211790 for a discussion and guide to related sequences.

Examples

			For n=2, the 3 triples (w,x,y) for which 2w<x+y are (1,1,2), (1,2,1), (1,2,2).  The 3 triples for which 2w>x+y are (2,1,1), (2,1,2), (2,2,1).
		

Crossrefs

Programs

  • Mathematica
    (See the program at A211802.)
    LinearRecurrence[{3,-2,-2,3,-1},{0,3,11,28,56},50] (* Harvey P. Dale, Aug 10 2019 *)

Formula

a(n) = 3*a(n-1)-2*a(n-2)-2*a(n-3)+3*a(n-4)-a(n-5).
From Colin Barker, May 06 2012: (Start)
a(n) = (-1+(-1)^n-2*n^2+4*n^3)/8.
G.f.: x^2*(3 + 2*x + x^2)/((1 - x)^4*(1 + x)). (End)

A182259 Rectangular array: R(k,n) = number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w^k<=x^k+y

Original entry on oeis.org

0, 3, 0, 11, 3, 0, 28, 11, 3, 0, 56, 28, 11, 3, 0, 99, 56, 26, 11, 3, 0, 159, 97, 52, 26, 11, 3, 0, 240, 153, 93, 50, 26, 11, 3, 0, 344, 230, 149, 85, 50, 26, 11, 3, 0, 475, 330, 222, 139, 85, 50, 26, 11, 3, 0, 635, 453, 314, 212, 133, 85, 50, 26, 11, 3, 0, 828
Offset: 1

Author

Clark Kimberling, Apr 22 2012

Keywords

Comments

Row 1: A182260
Row 2: A211810
Row 3: A211811
Limiting row sequence: A051925
Let R be the array in A211808 and let R' be the array in A182259. Then R(k,n)+R'(k,n)=3^(n-1).
See the Comments at A211790.

Examples

			Northwest corner (with antidiagonals read from northeast to southwest):
0...3...11...28...56...99...159
0...3...11...28...56...97...153
0...3...11...26...52...93...149
0...3...11...26...50...85...139
0...3...11...26...50...85...133
		

Crossrefs

Cf. A211790.

Programs

  • Mathematica
    z = 48;
    t[k_, n_] := Module[{s = 0},
       (Do[If[2 w^k > x^k + y^k, s = s + 1],
           {w, 1, #}, {x, 1, #}, {y, 1, #}] &[n]; s)];
    Table[t[1, n], {n, 1, z}]  (* A182260 *)
    Table[t[2, n], {n, 1, z}]  (* A211810 *)
    Table[t[3, n], {n, 1, z}]  (* A211811 *)
    TableForm[Table[t[k, n], {k, 1, 12}, {n, 1, 16}]]
    Flatten[Table[t[k, n - k + 1],
        {n, 1, 12}, {k, 1, n}]] (* A182259 *)
    Table[k (k - 1) (2 k + 5)/6,
        {k, 1, z}] (* row-limit sequence, A051925 *)
    (* Peter J. C. Moses, Apr 13 2012 *)

A211802 R(k,n) = number of ordered triples (w,x,y) with all terms in {1,...,n} and 2*w^k < x^k + y^k; square array read by descending antidiagonals.

Original entry on oeis.org

0, 3, 0, 11, 3, 0, 28, 13, 3, 0, 56, 32, 13, 3, 0, 99, 64, 34, 13, 3, 0, 159, 113, 68, 34, 13, 3, 0, 240, 181, 117, 70, 34, 13, 3, 0, 344, 272, 187, 125, 70, 34, 13, 3, 0, 475, 388, 282, 197, 125, 70, 34, 13, 3, 0, 635, 535, 406, 292, 203, 125, 70, 34, 13, 3, 0
Offset: 1

Author

Clark Kimberling, Apr 22 2012

Keywords

Comments

Row 1: A182260.
Row 2: A211800.
Row 3: A211801.
Limiting row sequence: A016061.
Let R be the array in this sequence and let R' be the array in A211805. Then R(k,n) + R'(k,n) = 3^(n-1).
See the Comments at A211790.

Examples

			Northwest corner:
  0   3  11  28  56  99 159 240
  0   3  13  32  64 113 181 272
  0   3  13  34  68 117 187 282
  0   3  13  34  70 125 197 292
  0   3  13  34  70 125 203 302
		

Programs

  • Mathematica
    z = 48;
    t[k_, n_] := Module[{s = 0},
       (Do[If[2 w^k < x^k + y^k, s = s + 1],
           {w, 1, #}, {x, 1, #}, {y, 1, #}] &[n]; s)];
    Table[t[1, n], {n, 1, z}]  (* A182260 *)
    Table[t[2, n], {n, 1, z}]  (* A211800 *)
    Table[t[3, n], {n, 1, z}]  (* A211801 *)
    TableForm[Table[t[k, n], {k, 1, 12}, {n, 1, 16}]]
    Flatten[Table[t[k, n - k + 1], {n, 1, 12},
                    {k, 1, n}]] (* this sequence *)
    Table[k (k - 1) (4 k + 1)/6, {k, 1,
      z}] (* row-limit sequence, A016061 *)
    (* Peter J. C. Moses, Apr 13 2012 *)

Extensions

Definition corrected by Georg Fischer, Sep 10 2022

A211805 Rectangular array: R(k,n) = number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w^k>=x^k+y

Original entry on oeis.org

1, 5, 1, 16, 5, 1, 36, 14, 5, 1, 69, 32, 14, 5, 1, 117, 61, 30, 14, 5, 1, 184, 103, 57, 30, 14, 5, 1, 272, 162, 99, 55, 30, 14, 5, 1, 385, 240, 156, 91, 55, 30, 14, 5, 1, 525, 341, 230, 146, 91, 55, 30, 14, 5, 1, 696, 465, 323, 220, 140, 91, 55, 30, 14, 5, 1, 900
Offset: 1

Author

Clark Kimberling, Apr 22 2012

Keywords

Comments

Row 1: A055232
Row 2: A211803
Row 3: A211804
Limiting row sequence: A000330
Let R be the array in A211802 and let R' be the array in A211805. Then R(k,n)+R'(k,n)=3^(n-1).
See the Comments at A211790.

Examples

			Northwest corner:
1...5...16...36...69...117...184
1...5...14...32...61...103...162
1...5...14...30...57...99....156
1...5...14...30...55...91....146
1...5...14...30...55...91....140
		

Crossrefs

Cf. A211790.

Programs

  • Mathematica
    z = 48;
    t[k_, n_] := Module[{s = 0},
       (Do[If[2 w^k >= x^k + y^k, s = s + 1],
           {w, 1, #}, {x, 1, #}, {y, 1, #}] &[n]; s)];
    Table[t[1, n], {n, 1, z}]  (* A055232 *)
    Table[t[2, n], {n, 1, z}]  (* A211803 *)
    Table[t[3, n], {n, 1, z}]  (* A211804 *)
    TableForm[Table[t[k, n], {k, 1, 12}, {n, 1, 16}]]
    Flatten[Table[t[k, n - k + 1], {n, 1, 12},
                   {k, 1, n}]] (* A211805 *)
    Table[k (k + 1) (2 k + 1)/6,
        {k, 1, z}] (* row-limit sequence, A000330 *)
    (* Peter J. C. Moses, Apr 13 2012 *)

A211808 Rectangular array: R(k,n) = number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w^k<=x^k+y

Original entry on oeis.org

1, 5, 1, 16, 5, 1, 36, 16, 5, 1, 69, 36, 16, 5, 1, 117, 69, 38, 16, 5, 1, 184, 119, 73, 38, 16, 5, 1, 272, 190, 123, 75, 38, 16, 5, 1, 385, 282, 194, 131, 75, 38, 16, 5, 1, 525, 399, 290, 204, 131, 75, 38, 16, 5, 1, 696, 547, 415, 300, 210, 131, 75, 38, 16, 5, 1
Offset: 1

Author

Clark Kimberling, Apr 22 2012

Keywords

Comments

Row 1: A055232
Row 2: A211806
Row 3: A211807
Limiting row sequence: A000330
Let R be the array in A211808 and let R' be the array in A182259. Then R(k,n)+R'(k,n)=3^(n-1).
See the Comments at A211790.

Examples

			Northwest corner:
1...5...16...36...69...117...184
1...5...16...36...69...119...190
1...5...16...38...73...123...194
1...5...16...38...75...131...204
1...5...16...38...75...131...210
		

Crossrefs

Cf. A211790.

Programs

  • Mathematica
    z = 48;
    t[k_, n_] := Module[{s = 0},
       (Do[If[2 w^k <= x^k + y^k, s = s + 1],
           {w, 1, #}, {x, 1, #}, {y, 1, #}] &[n]; s)];
    Table[t[1, n], {n, 1, z}]  (* A055232 *)
    Table[t[2, n], {n, 1, z}]  (* A211806 *)
    Table[t[3, n], {n, 1, z}]  (* A211807 *)
    TableForm[Table[t[k, n], {k, 1, 12}, {n, 1, 16}]]
    Flatten[Table[t[k, n - k + 1],
         {n, 1, 12}, {k, 1, n}]] (* A211808 *)
    Table[k (4 k^2 - 3 k + 5)/6,
         {k, 1, z}] (* row-limit sequence, A174723 *)
    (* Peter J. C. Moses, Apr 13 2012 *)

A211796 Rectangular array: R(k,n) = number of ordered triples (w,x,y) with all terms in {1,...,n} and w^k<=x^k+y^k.

Original entry on oeis.org

1, 8, 1, 26, 7, 1, 60, 22, 7, 1, 115, 51, 22, 7, 1, 196, 99, 50, 22, 7, 1, 308, 168, 96, 50, 22, 7, 1, 456, 265, 163, 95, 50, 22, 7, 1, 645, 393, 255, 161, 95, 50, 22, 7, 1, 880, 556, 378, 253, 161, 95, 50, 22, 7, 1, 1166, 760, 534, 374, 252, 161, 95, 50, 22, 7
Offset: 1

Author

Clark Kimberling, Apr 21 2012

Keywords

Comments

Row 1: A002413
Row 2: A211634
Row 3: A211650
Limiting row sequence: A002412
Let R be the array in A211796 and let R' be the array in A211799. Then R(k,n)+R'(k,n)=3^(n-1).
See the Comments at A211790.

Examples

			Northwest corner:
1...8...26...60...115...196...308
1...7...22...51...99....168...265
1...7...22...50...96....163...255
1...7...22...50...95....161...253
1...7...22...50...95....161...252
		

Crossrefs

Cf. A211790.

Programs

  • Mathematica
    z = 48;
    t[k_, n_] := Module[{s = 0},
       (Do[If[w^k <= x^k + y^k, s = s + 1],
           {w, 1, #}, {x, 1, #}, {y, 1, #}] &[n]; s)];
    Table[t[1, n], {n, 1, z}]  (* A002413 *)
    Table[t[2, n], {n, 1, z}]  (* A211634 *)
    Table[t[3, n], {n, 1, z}]  (* A211650 *)
    TableForm[Table[t[k, n], {k, 1, 12}, {n, 1, 16}]]
    Flatten[Table[t[k, n - k + 1], {n, 1, 12}, {k, 1, n}]] (* A211796 *)
    Table[k (k - 1) (2 k - 1)/6, {k, 1,
      z}] (* row-limit sequence, A002412 *)
    (* Peter J. C. Moses, Apr 13 2012 *)

A211799 Rectangular array: R(k,n) = number of ordered triples (w,x,y) with all terms in {1,...,n} and w^k<=x^k+y

Original entry on oeis.org

0, 0, 0, 1, 1, 0, 4, 5, 1, 0, 10, 13, 5, 1, 0, 20, 26, 14, 5, 1, 0, 35, 48, 29, 14, 5, 1, 0, 56, 78, 53, 30, 14, 5, 1, 0, 84, 119, 88, 55, 30, 14, 5, 1, 0, 120, 173, 134, 90, 55, 30, 14, 5, 1, 0, 165, 240, 195, 138, 91, 55, 30, 14, 5, 1, 0, 220, 323, 270, 201, 139, 91
Offset: 1

Author

Clark Kimberling, Apr 21 2012

Keywords

Comments

Row 1: A002292
Row 2: A211637
Row 3: A211651
Limiting row sequence: A000330
Let R be the array in A211796 and let R' be the array in A211799. Then R(k,n)+R'(k,n)=3^(n-1).
See the Comments at A211790.

Examples

			Northwest corner:
0...0...1...4....10...20...35...56
0...1...5...13...26...48...78...119
0...1...5...14...29...53...88...134
0...1...5...14...30...55...90...138
0...1...5...14...30...55...91...139
		

Crossrefs

Cf. A211790.

Programs

  • Mathematica
    z = 48;
    t[k_, n_] := Module[{s = 0},
       (Do[If[w^k > x^k + y^k, s = s + 1],
           {w, 1, #}, {x, 1, #}, {y, 1, #}] &[n]; s)];
    Table[t[1, n], {n, 1, z}]  (* A000292 *)
    Table[t[2, n], {n, 1, z}]  (* A211637 *)
    Table[t[3, n], {n, 1, z}]  (* A211651 *)
    TableForm[Table[t[k, n], {k, 1, 12}, {n, 1, 16}]]
    Flatten[Table[t[k, n - k + 1],
        {n, 1, 12}, {k, 1, n}]] (* A211799 *)
    Table[k (k - 1) (2 k - 1)/6,
        {k, 1, z}] (* row-limit sequence, A000330 *)
    (* Peter J. C. Moses, Apr 13 2012 *)

A211801 Number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w^3

Original entry on oeis.org

0, 3, 13, 34, 68, 117, 187, 282, 406, 559, 743, 966, 1232, 1545, 1899, 2304, 2764, 3285, 3869, 4512, 5222, 6005, 6867, 7812, 8828, 9931, 11125, 12412, 13798, 15271, 16847, 18532, 20330, 22239, 24255, 26394, 28660, 31055, 33573, 36222
Offset: 1

Author

Clark Kimberling, Apr 22 2012

Keywords

Comments

Row 3 of A211802; see A211790 for a discussion and guide to related sequences.

Crossrefs

Programs

  • Mathematica
    (See the program at A211802.)

A211807 Number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w^3<=x^3+y^3.

Original entry on oeis.org

1, 5, 16, 38, 73, 123, 194, 290, 415, 569, 754, 978, 1245, 1559, 1914, 2320, 2781, 3303, 3888, 4532, 5243, 6027, 6890, 7836, 8853, 9957, 11152, 12440, 13827, 15301, 16878, 18564, 20363, 22273, 24290, 26430, 28697, 31093, 33612, 36262
Offset: 1

Author

Clark Kimberling, Apr 22 2012

Keywords

Comments

Row 3 of A211808; see A211790 for a discussion and guide to related sequences.

Crossrefs

Programs

  • Maple
    f:= proc(n) local x;
      n + add(2*floor(((x^3+n^3)/2)^(1/3)), x=1..n-1)
    end proc:
    ListTools:-PartialSums(map(f,[$1..50])); # Robert Israel, Jan 26 2025
  • Mathematica
    (See the program at A211808.)
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