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 1-5 of 5 results.

A352361 Array read by ascending antidiagonals. A(n, k) = Fibonacci(k, n), where Fibonacci(n, x) are the Fibonacci polynomials.

Original entry on oeis.org

0, 0, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1, 2, 2, 0, 0, 1, 3, 5, 3, 1, 0, 1, 4, 10, 12, 5, 0, 0, 1, 5, 17, 33, 29, 8, 1, 0, 1, 6, 26, 72, 109, 70, 13, 0, 0, 1, 7, 37, 135, 305, 360, 169, 21, 1, 0, 1, 8, 50, 228, 701, 1292, 1189, 408, 34, 0, 0, 1, 9, 65, 357, 1405, 3640, 5473, 3927, 985, 55, 1
Offset: 0

Views

Author

Peter Luschny, Mar 18 2022

Keywords

Comments

From Michael A. Allen, Mar 26 2023: (Start)
Row n is the n-metallonacci sequence for n>0.
A(n,k), for n > 0 and k > 0, is the number of tilings of a (k-1)-board (a board with dimensions (k-1) X 1) using unit squares and dominoes (with dimensions 2 X 1) if there are n kinds of squares available. (End)

Examples

			Array, A(n,k), starts:
  n\k 0, 1, 2,  3,   4,    5,     6,      7,       8,        9, ...
  -------------------------------------------------------------------------
  [0] 0, 1, 0,  1,   0,    1,     0,      1,       0,        1, ... A000035;
  [1] 0, 1, 1,  2,   3,    5,     8,     13,      21,       34, ... A000045;
  [2] 0, 1, 2,  5,  12,   29,    70,    169,     408,      985, ... A000129;
  [3] 0, 1, 3, 10,  33,  109,   360,   1189,    3927,    12970, ... A006190;
  [4] 0, 1, 4, 17,  72,  305,  1292,   5473,   23184,    98209, ... A001076;
  [5] 0, 1, 5, 26, 135,  701,  3640,  18901,   98145,   509626, ... A052918;
  [6] 0, 1, 6, 37, 228, 1405,  8658,  53353,  328776,  2026009, ... A005668;
  [7] 0, 1, 7, 50, 357, 2549, 18200, 129949,  927843,  6624850, ... A054413;
  [8] 0, 1, 8, 65, 528, 4289, 34840, 283009, 2298912, 18674305, ... A041025;
  [9] 0, 1, 9, 82, 747, 6805, 61992, 564733, 5144589, 46866034, ... A099371;
      |  |  |  | A054602 |   A124152;
      |  |  |  A002522   A057721;
      |  |  A001477;
      |  A000012;
      A000004;
Antidiagonals, T(n, k), begin as:
  0;
  0, 1;
  0, 1, 0;
  0, 1, 1,  1;
  0, 1, 2,  2,   0;
  0, 1, 3,  5,   3,   1;
  0, 1, 4, 10,  12,   5,   0;
  0, 1, 5, 17,  33,  29,   8,   1;
  0, 1, 6, 26,  72, 109,  70,  13,  0;
  0, 1, 7, 37, 135, 305, 360, 169, 21, 1;
		

Crossrefs

Other versions of this array are A073133, A157103, A172236.
Rows n: A000035 (n=0), A000045 (n=1), A000129 (n=2), A006190 (n=3), A001076 (n=4), A052918 (n=5), A005668 (n=6), A054413 (n=7), A041025 (n=8), A099371 (n=9).
Columns k: A000004 (k=0), A000012 (k=1), A001477 (k=2), A002522 (k=3), A054602 (k=4), A057721 (k=5), A124152 (k=6).
Cf. A084844 (main diagonal), A352362 (Lucas polynomials), A350470 (Jacobsthal polynomials).
Sums include: A304357 (row sums), A304359.
Cf. A084845.

Programs

  • Magma
    A352361:= func< n, k | k le 1 select k else Evaluate(DicksonSecond(k-1, -1), n-k) >;
    [A352361(n, k): k in [0..n], n in [0..13]]; // G. C. Greubel, Sep 29 2024
    
  • Maple
    seq(seq(combinat:-fibonacci(k, n - k), k = 0..n), n = 0..11);
  • Mathematica
    Table[Fibonacci[k, n - k], {n, 0, 9}, {k, 0, n}] // Flatten
    (* or *)
    A[n_, k_] := With[{s = Sqrt[n^2 + 4]}, ((n + s)^k - (n - s)^k) / (2^k*s)];
    Table[Simplify[A[n, k]], {n, 0, 9}, {k, 0, 9}] // TableForm
  • PARI
    A(n, k) = ([1, k; 1, k-1]^n)[2, 1] ;
    export(A)
    for(k = 0, 9, print(parvector(10, n, A(n - 1, k))))
    
  • SageMath
    def A352361(n, k): return lucas_number1(k,n-k,-1)
    flatten([[A352361(n, k) for k in range(n+1)] for n in range(14)]) # G. C. Greubel, Sep 29 2024

Formula

A(n, k) = Sum_{j=0..floor((k-1)/2)} binomial(k-j-1, j)*n^(k-2*j-1).
A(n, k) = ((n + s)^k - (n - s)^k) / (2^k*s) where s = sqrt(n^2 + 4).
A(n, k) = [x^k] (x / (1 - n*x - x^2)).
A(n, k) = n^(k-1)*hypergeom([1 - k/2, 1/2 - k/2], [1 - k], -4/n^2) for n,k >= 1.
A(n, n) = T(2*n, n) = A084844(n).
From G. C. Greubel, Sep 29 2024: (Start)
T(n, k) = A(n-k, k) (antidiagonal triangle).
T(2*n+1, n+1) = A084845(n).
Sum_{k=0..n} T(n, k) = A304357(n) (row sums).
Sum_{k=0..n} (-1)^k*T(n, k) = (-1)*A304359(n). (End)

A352362 Array read by ascending antidiagonals. T(n, k) = L(k, n) where L are the Lucas polynomials.

Original entry on oeis.org

2, 2, 0, 2, 1, 2, 2, 2, 3, 0, 2, 3, 6, 4, 2, 2, 4, 11, 14, 7, 0, 2, 5, 18, 36, 34, 11, 2, 2, 6, 27, 76, 119, 82, 18, 0, 2, 7, 38, 140, 322, 393, 198, 29, 2, 2, 8, 51, 234, 727, 1364, 1298, 478, 47, 0, 2, 9, 66, 364, 1442, 3775, 5778, 4287, 1154, 76, 2
Offset: 0

Views

Author

Peter Luschny, Mar 18 2022

Keywords

Examples

			Array starts:
n\k 0, 1,  2,   3,    4,     5,      6,       7,        8, ...
--------------------------------------------------------------
[0] 2, 0,  2,   0,    2,     0,      2,       0,        2, ... A010673
[1] 2, 1,  3,   4,    7,    11,     18,      29,       47, ... A000032
[2] 2, 2,  6,  14,   34,    82,    198,     478,     1154, ... A002203
[3] 2, 3, 11,  36,  119,   393,   1298,    4287,    14159, ... A006497
[4] 2, 4, 18,  76,  322,  1364,   5778,   24476,   103682, ... A014448
[5] 2, 5, 27, 140,  727,  3775,  19602,  101785,   528527, ... A087130
[6] 2, 6, 38, 234, 1442,  8886,  54758,  337434,  2079362, ... A085447
[7] 2, 7, 51, 364, 2599, 18557, 132498,  946043,  6754799, ... A086902
[8] 2, 8, 66, 536, 4354, 35368, 287298, 2333752, 18957314, ... A086594
[9] 2, 9, 83, 756, 6887, 62739, 571538, 5206581, 47430767, ... A087798
A007395|A059100|
    A001477 A079908
		

Crossrefs

Cf. A320570 (main diagonal), A114525, A309220 (variant), A117938 (variant), A352361 (Fibonacci polynomials), A350470 (Jacobsthal polynomials).

Programs

  • Maple
    T := (n, k) -> (n/2 + sqrt((n/2)^2 + 1))^k + (n/2 - sqrt((n/2)^2 + 1))^k:
    seq(seq(simplify(T(n - k, k)), k = 0..n), n = 0..10);
  • Mathematica
    Table[LucasL[k, n], {n, 0, 9}, {k, 0, 9}] // TableForm
    (* or *)
    T[ 0, k_] := 2 Mod[k+1, 2]; T[n_, 0] := 2;
    T[n_, k_] := n^k Hypergeometric2F1[1/2 - k/2, -k/2, 1 - k, -4/n^2];
    Table[T[n, k], {n, 0, 9}, {k, 0, 8}] // TableForm
  • PARI
    T(n, k) = ([0, 1; 1, k]^n*[2; k])[1, 1] ;
    export(T)
    for(k = 0, 9, print(parvector(10, n, T(n - 1, k))))

Formula

T(n, k) = Sum_{j=0..floor(k/2)} binomial(k-j, j)*(k/(k-j))*n^(k-2*j) for k >= 1.
T(n, k) = (n/2 + sqrt((n/2)^2 + 1))^k + (n/2 - sqrt((n/2)^2 + 1))^k.
T(n, k) = [x^k] ((2 - n*x)/(1 - n*x - x^2)).
T(n, k) = n^k*hypergeom([1/2 - k/2, -k/2], [1 - k], -4/n^2) for n,k >= 1.

A350467 a(n) = hypergeom([1/2 - n/2, -n/2], [-n], -8*n).

Original entry on oeis.org

1, 1, 5, 13, 89, 341, 2653, 13021, 110449, 648469, 5891381, 39734685, 382729801, 2887493077, 29287115341, 242592910621, 2577978650081, 23125601566165, 256460946182821, 2465492129670493, 28441473938165561, 290630718826209301, 3477967327342044989, 37528922270996471133
Offset: 0

Views

Author

Peter Luschny, Mar 19 2022

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Hypergeometric2F1[(1 - n)/2, -n/2, -n, -8 n ], {n, 0, 23}]
    Table[FullSimplify[((1 + Sqrt[8*n + 1])^(n+1) - (1 - Sqrt[8*n + 1])^(n+1)) / (Sqrt[8*n + 1] * 2^(n+1))], {n, 0, 25}] (* Vaclav Kotesovec, Jan 08 2024 *)

Formula

a(n) = Sum_{k=0..n} binomial(n - k, k)*(2*n)^k.
a(n) = A350470(n, n).
From Vaclav Kotesovec, Jan 08 2024: (Start)
a(n) = ((1 + sqrt(8*n+1))^(n+1) - (1 - sqrt(8*n+1))^(n+1)) / (sqrt(8*n+1) * 2^(n+1)).
a(n) ~ exp(sqrt(n/2)/2) * 2^(n/2 - 1) * n^(n/2) * (1 + 47/(96*sqrt(2*n))). (End)

A350468 a(n) = hypergeom([1/2 - n/2, -n/2], [-n], -56).

Original entry on oeis.org

1, 1, 15, 29, 239, 645, 3991, 13021, 68895, 251189, 1215719, 4732365, 21752431, 88005541, 392539575, 1624617149, 7120171199, 29864811285, 129547208071, 547654566061, 2361315479055, 10028479403909, 43086896110679, 183485607765405, 786702153314911, 3355500662030581
Offset: 0

Views

Author

Peter Luschny, Mar 19 2022

Keywords

Crossrefs

a(n) = A350470(7, n).

Programs

  • Mathematica
    Table[HypergeometricPFQ[{1/2 - n/2, -n/2}, {-n}, -56], {n, 0, 30}] (* Vaclav Kotesovec, Feb 18 2024 *)

Formula

a(n) ~ (1 + sqrt(57))^(n+1) / (sqrt(57) * 2^(n+1)). - Vaclav Kotesovec, Feb 18 2024

A350469 a(n) = hypergeom([1/2 - n/2, -n/2], [-n], -72).

Original entry on oeis.org

1, 1, 19, 37, 379, 1045, 7867, 26677, 168283, 648469, 3677563, 15350005, 81546139, 357846229, 1825676731, 8266908853, 41129090011, 189933449365, 930257069563, 4349059158133, 21093686410267, 99376751256661, 479063106641467, 2267844629261365, 10890980548807771
Offset: 0

Views

Author

Peter Luschny, Mar 19 2022

Keywords

Crossrefs

a(n) = A350470(9, n).

Programs

  • Mathematica
    Table[HypergeometricPFQ[{1/2 - n/2, -n/2}, {-n}, -72], {n, 0, 30}] (* Vaclav Kotesovec, Feb 18 2024 *)

Formula

a(n) ~ (1 + sqrt(73))^(n+1) / (sqrt(73) * 2^(n+1)). - Vaclav Kotesovec, Feb 18 2024
Showing 1-5 of 5 results.