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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A259598 Number of representations of n as u(h) + v(k), where u = A000201 (lower Wythoff numbers), v = A001950 (upper Wythoff numbers), h>=1, k>=1.

Original entry on oeis.org

0, 0, 1, 0, 1, 2, 0, 3, 1, 2, 4, 0, 4, 4, 1, 6, 2, 4, 7, 0, 8, 4, 4, 9, 1, 8, 8, 2, 11, 4, 7, 12, 0, 12, 9, 4, 14, 4, 10, 14, 1, 16, 8, 8, 17, 2, 15, 14, 4, 19, 7, 12, 20, 0, 21, 12, 9, 22, 4, 18, 19, 4, 24, 10, 14, 25, 1, 24, 18, 8, 27, 8, 19, 26, 2, 29, 15
Offset: 1

Views

Author

Clark Kimberling, Jul 22 2015

Keywords

Comments

Three conjectures. The numbers that are not a sum u(h) + v(k) are (1,2,4,7,12, ...) = A000071 = -1 + Fibonacci numbers. The numbers that have exactly one such representation are (3, 5, 9, 15, 25, 41, ...) = A001595. The numbers that have exactly two such representations are (6, 10, 17, 28, 46, ...) = A001610.

Crossrefs

Programs

  • Mathematica
    r = GoldenRatio; z = 500;
    u[n_] := u[n] = Floor[n*r]; v[n_] := v[n] = Floor[n*r^2];
    s[m_, n_] := s[m, n] = u[m] + v[n]; t = Table[s[m, n], {m, 1, z}, {n, 1, z}];
    w = Flatten[Table[Count[Flatten[t], n], {n, 1, z/5}]]  (* A259598 *)
  • PARI
    {a(n) = my(phi = (1 + sqrt(5))/2, WL=1, WU=1);
    WL = sum(m=1, floor(n/phi)+1, x^floor(m*phi) +x*O(x^n));
    WU = sum(m=1, floor(n/phi^2)+1, x^floor(m*phi^2) +x*O(x^n));
    polcoeff(WL*WU, n)}
    for(n=1, 120, print1(a(n), ", ")) \\ Paul D. Hanna, Dec 02 2017

Formula

G.f.: [Sum_{n>=1} x^floor(n*phi)] * [Sum_{n>=1} x^floor(n*phi^2)], where phi = (1+sqrt(5))/2. - Paul D. Hanna, Dec 02 2017
G.f.: [Sum_{n>=1} x^A000201(n)] * [Sum_{n>=1} x^A001950(n)], where A000201 and A001950 are the lower and upper Wythoff sequences, respectively. - Paul D. Hanna, Dec 02 2017

A283767 Numbers k such that U(k) is even, where U = A001950 = upper Wythoff sequence.

Original entry on oeis.org

1, 4, 7, 8, 10, 11, 13, 14, 17, 20, 21, 23, 24, 26, 27, 30, 33, 36, 37, 39, 40, 43, 46, 49, 50, 52, 53, 56, 59, 62, 63, 65, 66, 68, 69, 72, 75, 76, 78, 79, 81, 82, 85, 88, 91, 92, 94, 95, 98, 101, 104, 105, 107, 108, 111, 114, 117, 118, 120, 121, 123, 124
Offset: 1

Views

Author

Clark Kimberling, Mar 17 2017

Keywords

Comments

Complement of A283768.

Crossrefs

Programs

  • Mathematica
    r = GoldenRatio^2; z = 250; t = Table[Floor[n*r], {n, 1, z}]; u = Mod[t, 2];
    Flatten[Position[u, 0]]  (* A283767 *)
    Flatten[Position[u, 1]]  (* A283768 *)

Formula

a(n+1) - a(n) is in {1,2,3} for every n.

A283768 Numbers k such that U(k) is odd, where U = A001950 = upper Wythoff sequence.

Original entry on oeis.org

2, 3, 5, 6, 9, 12, 15, 16, 18, 19, 22, 25, 28, 29, 31, 32, 34, 35, 38, 41, 42, 44, 45, 47, 48, 51, 54, 55, 57, 58, 60, 61, 64, 67, 70, 71, 73, 74, 77, 80, 83, 84, 86, 87, 89, 90, 93, 96, 97, 99, 100, 102, 103, 106, 109, 110, 112, 113, 115, 116, 119, 122, 125
Offset: 1

Views

Author

Clark Kimberling, Mar 17 2017

Keywords

Comments

Complement of A283767.

Crossrefs

Programs

  • Mathematica
    r = GoldenRatio^2; z = 250; t = Table[Floor[n*r], {n, 1, z}]; u = Mod[t, 2];
    Flatten[Position[u, 0]]  (* A283767 *)
    Flatten[Position[u, 1]]  (* A283768 *)

Formula

a(n+1) - a(n) is in {1,2,3} for every n.

A283772 Numbers k such that U(k) = 0 mod 3, where U = A001950 = upper Wythoff sequence.

Original entry on oeis.org

6, 7, 14, 15, 21, 22, 23, 29, 30, 31, 37, 38, 39, 45, 46, 47, 53, 54, 61, 62, 69, 70, 76, 77, 78, 84, 85, 86, 92, 93, 94, 100, 101, 102, 108, 109, 116, 117, 124, 125, 131, 132, 133, 139, 140, 141, 147, 148, 149, 155, 156, 157, 163, 164, 171, 172, 179, 180
Offset: 1

Views

Author

Clark Kimberling, Mar 18 2017

Keywords

Comments

The sequences A283772, A283773, A283774 partition the positive integers.

Crossrefs

Programs

  • Mathematica
    r = GoldenRatio^2; z = 350; t = Table[Floor[n*r], {n, 1, z}]; u = Mod[t, 3];
    Flatten[Position[u, 0]]  (* A283772 *)
    Flatten[Position[u, 1]]  (* A283773 *)
    Flatten[Position[u, 2]]  (* A283774 *)
  • PARI
    r = (3 + sqrt(5))/2;
    for(n=1, 351, if(floor(n*r)%3==0, print1(n,", "))) \\ Indranil Ghosh, Mar 19 2017
    
  • Python
    import math
    from sympy import sqrt
    r = (3 + sqrt(5))/2
    [n for n in range(1, 351) if int(math.floor(n*r))%3==0] # Indranil Ghosh, Mar 19 2017

Formula

a(n+1) - a(n) is in {1,6,7} for every n.

A283773 Numbers k such that U(k) = 1 mod 3, where U = A001950 = upper Wythoff sequence.

Original entry on oeis.org

3, 4, 5, 11, 12, 13, 19, 20, 27, 28, 35, 36, 42, 43, 44, 50, 51, 52, 58, 59, 60, 66, 67, 68, 74, 75, 82, 83, 90, 91, 97, 98, 99, 105, 106, 107, 113, 114, 115, 121, 122, 123, 129, 130, 137, 138, 144, 145, 146, 152, 153, 154, 160, 161, 162, 168, 169, 170, 176
Offset: 1

Views

Author

Clark Kimberling, Mar 18 2017

Keywords

Comments

The sequences A283772, A283773, A283774 partition the positive integers.

Crossrefs

Programs

  • Mathematica
    r = GoldenRatio^2; z = 350; t = Table[Floor[n*r], {n, 1, z}]; u = Mod[t, 3];
    Flatten[Position[u, 0]]  (* A283772 *)
    Flatten[Position[u, 1]]  (* A283773 *)
    Flatten[Position[u, 2]]  (* A283774 *)
  • PARI
    r = (3 + sqrt(5))/2;
    for(n=1, 351, if(floor(n*r)%3==1, print1(n,", "))) \\ Indranil Ghosh, Mar 19 2017
    
  • Python
    import math
    from sympy import sqrt
    r = (3 + sqrt(5))/2
    [n for n in range(1, 351) if int(math.floor(n*r))%3==1] # Indranil Ghosh, Mar 19 2017

Formula

a(n+1) - a(n) is in {1,6,7} for every n.

A283774 Numbers k such that U(k) == 2 mod 3, where U = A001950 = upper Wythoff sequence.

Original entry on oeis.org

1, 2, 8, 9, 10, 16, 17, 18, 24, 25, 26, 32, 33, 34, 40, 41, 48, 49, 55, 56, 57, 63, 64, 65, 71, 72, 73, 79, 80, 81, 87, 88, 89, 95, 96, 103, 104, 110, 111, 112, 118, 119, 120, 126, 127, 128, 134, 135, 136, 142, 143, 150, 151, 158, 159, 165, 166, 167, 173
Offset: 1

Views

Author

Clark Kimberling, Mar 19 2017

Keywords

Comments

The sequences A283772, A283773, A283774 partition the positive integers.

Crossrefs

Programs

  • Mathematica
    r = GoldenRatio^2; z = 350; t = Table[Floor[n*r], {n, 1, z}]; u = Mod[t, 3];
    Flatten[Position[u, 0]]  (* A283772 *)
    Flatten[Position[u, 1]]  (* A283773 *)
    Flatten[Position[u, 2]]  (* A283774 *)
  • PARI
    r = (3 + sqrt(5))/2;
    for(n=1, 351, if(floor(n*r)%3==2, print1(n, ", "))) \\ Indranil Ghosh, Mar 21 2017
    
  • Python
    import math
    from sympy import sqrt
    r = (3 + sqrt(5))/2
    [n for n in range(1, 351) if int(math.floor(n*r))%3==2] # Indranil Ghosh, Mar 21 2017

Formula

a(n+1) - a(n) is in {1,6,7} for every n.

A289926 p-INVERT of the upper Wythoff sequence (A001950), where p(S) = 1 - S - S^2.

Original entry on oeis.org

2, 13, 71, 376, 1991, 10564, 56051, 297384, 1577797, 8371133, 44413759, 235640987, 1250213362, 6633113651, 35192550325, 186717077925, 990643385291, 5255942989944, 27885853904294, 147950776760552, 784965467407868, 4164701250741605, 22096177765889378
Offset: 0

Views

Author

Clark Kimberling, Aug 14 2017

Keywords

Comments

Suppose s = (c(0), c(1), c(2), ...) is a sequence and p(S) is a polynomial. Let S(x) = c(0)*x + c(1)*x^2 + c(2)*x^3 + ... and T(x) = (-p(0) + 1/p(S(x)))/x. The p-INVERT of s is the sequence t(s) of coefficients in the Maclaurin series for T(x). Taking p(S) = 1 - S gives the "INVERT" transform of s, so that p-INVERT is a generalization of the "INVERT" transform (e.g., A033453).
See A289780 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; r = 1 + GoldenRatio; s = Sum[Floor[k*r] x^k, {k, 1, z}]; p = 1 - s - s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A001950 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x] , 1]  (* A289926 *)

A356106 a(n) = A001950(A022839(n)).

Original entry on oeis.org

5, 10, 15, 20, 28, 34, 39, 44, 52, 57, 62, 68, 75, 81, 86, 91, 99, 104, 109, 115, 120, 128, 133, 138, 143, 151, 157, 162, 167, 175, 180, 185, 191, 198, 204, 209, 214, 219, 227, 233, 238, 243, 251, 256, 261, 267, 274, 280, 285, 290, 298, 303, 308, 314, 319
Offset: 1

Views

Author

Clark Kimberling, Sep 08 2022

Keywords

Comments

This is the third of four sequences that partition the positive integers. See A356104.

Examples

			(1)  u o v = (3, 6, 9, 12, 17, 21, 24, 27, 32, 35, 38, 42, 46, ...) = A356104
(2)  u o v' = (1, 4, 8, 11, 14, 16, 19, 22, 25, 29, 30, 33, 37, ...) = A356105
(3)  u' o v = (5, 10, 15, 20, 28, 34, 39, 44, 52, 57, 62, 68, ...) = this sequence
(4)  u' o v' = (2, 7, 13, 18, 23, 26, 31, 36, 41, 47, 49, 54, ...) = A356107
		

Crossrefs

Cf. u = A000201, u' = A001950, v = A022839, v' = A108598, A356104, A356105, A356107, A351415 (intersections), A356217 (reverse composites).

Programs

  • Mathematica
    z = 1000;
    u = Table[Floor[n*(1 + Sqrt[5])/2], {n, 1, z}];  (* A000201 *)
    u1 = Complement[Range[Max[u]], u];  (* A001950 *)
    v = Table[Floor[n*Sqrt[5]], {n, 1, z}];  (* A022839 *)
    v1 = Complement[Range[Max[v]], v];  (* A108598 *)
    zz = 120;
    Table[u[[v[[n]]]], {n, 1, zz}]    (* A356104 *)
    Table[u[[v1[[n]]]], {n, 1, zz}]   (* A356105 *)
    Table[u1[[v[[n]]]], {n, 1, zz}]   (* this sequence *)
    Table[u1[[v1[[n]]]], {n, 1, zz}]  (* A356107 *)

Extensions

Definition corrected by Georg Fischer, May 24 2024

A192185 Number of partitions of n into upper Wythoff numbers (A001950).

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 1, 2, 1, 2, 3, 2, 4, 3, 5, 6, 5, 8, 7, 9, 13, 10, 16, 14, 18, 22, 21, 28, 29, 31, 42, 37, 50, 51, 57, 70, 69, 83, 91, 95, 120, 118, 139, 153, 161, 193, 200, 224, 254, 262, 312, 324, 360, 404, 427, 485, 525, 561, 640, 668, 758, 817, 878, 982, 1046, 1150, 1265, 1340, 1499, 1597, 1745, 1911, 2036, 2241, 2420, 2602, 2866, 3041, 3332, 3597, 3864, 4221, 4518
Offset: 0

Views

Author

Paul D. Hanna, Jun 25 2011

Keywords

Comments

This sequence is motivated by the identity:
Product_{n>=1} (1 - x^[n*phi])*(1 - x^[n*phi^2]) / (1 - x^n) = 1, where [.] denotes floor(.).
Therefore, the product of the g.f. of this sequence with the g.f. of A192184 yields the g.f. of the partition numbers (A000041).

Examples

			G.f.: A(x) = 1 + x^2 + x^4 + x^5 + x^6 + 2*x^7 + x^8 + 2*x^9 + 3*x^10 +...
where the g.f. may be expressed by the product:
A(x) = 1/((1-x^2)*(1-x^5)*(1-x^7)*(1-x^10)*(1-x^13)*...)
in which the exponents of x are the upper Wythoff numbers (A001950):
[2,5,7,10,13,15,18,20,23,26,28,31,34,36,39,41,44,47,49,52,54,57,60,...].
a(12) counts these partitions: [10,2], [7,5], [5,5,2], [2,2,2,2,2,2]. _Clark Kimberling_, Mar 09 2014
		

Crossrefs

Programs

  • Mathematica
    t = Table[Floor[n+n*GoldenRatio], {n, 1, 200}]; p[n_] := IntegerPartitions[n, All, t]; Table[ p[n], {n, 0, 12}] (*shows partitions*)
    a[n_] := Length@p@n; a /@ Range[0, 80]
    (* Clark Kimberling, Mar 09 2014 *)
  • PARI
    {a(n)=local(phi=(sqrt(5)+1)/2,PWU=1/prod(m=1,ceil(n/phi),1-x^floor(m*phi^2)+x*O(x^n)));polcoeff(PWU,n)}

Formula

G.f.: Product_{n>=1} 1/(1 - x^floor(n*phi^2)), where phi = (sqrt(5)+1)/2.
G.f.: Product_{n>=1} 1/(1 - x^A001950(n)), where A001950 is the upper Wythoff sequence.

A203237 (n-1)-st elementary symmetric function of the first n terms of the upper Wythoff sequence, A001950.

Original entry on oeis.org

1, 7, 59, 660, 9280, 148300, 2805900, 58575000, 1396365000, 37435710000, 1077585600000, 34227953760000, 1189257232800000, 43680491749440000, 1734759507499200000, 72342732649037760000, 3233001543062054400000
Offset: 1

Views

Author

Clark Kimberling, Dec 30 2011

Keywords

Crossrefs

Cf. A203236.

Programs

  • Mathematica
    f[k_] := k + Floor[GoldenRatio*k]
    t[n_] := Table[f[k], {k, 1, n}]
    a[n_] := SymmetricPolynomial[n - 1, t[n]]
    Table[a[n], {n, 1, 18}]     (* A203237 *)
    t[16]  (* A001950 *)
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