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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A289845 p-INVERT of A079977, where p(S) = 1 - S - S^2.

Original entry on oeis.org

1, 2, 4, 9, 19, 43, 91, 202, 433, 952, 2055, 4494, 9737, 21236, 46099, 100403, 218164, 474833, 1032256, 2245929, 4883690, 10623848, 23103985, 50255443, 109298635, 237734446, 517055409, 1124617945, 2446001258, 5320100761, 11571106298, 25167245524, 54738437517
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; s = -x/(x^4 + x^2 - 1); p = 1 - s - s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A079977 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1] (*A289845*)
    LinearRecurrence[{1,3,-1,1,-1,-2,0,-1},{1,2,4,9,19,43,91,202},40] (* Harvey P. Dale, Jan 16 2019 *)

Formula

G.f.: (1 + x - x^2 - x^4)/(1 - x - 3 x^2 + x^3 - x^4 + x^5 + 2 x^6 + x^8).
a(n) = a(n-1) + 3*a(n-2) - a(n-3) + a(n-4) - a(n-5) - 2*a(n-6) - a(n-8).

A289924 p-INVERT of (n!), n >= 1 (A000142, shifted), where p(S) = 1 - S - S^2.

Original entry on oeis.org

1, 4, 17, 79, 402, 2253, 14037, 98152, 774973, 6911131, 69225314, 771593257, 9470565513, 126755983488, 1834510979193, 28511931874423, 473179672441090, 8346048191981797, 155838573499885229, 3069991622444141848, 63618933765102190149, 1383222300396890185731
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

Cf. A000142.

Programs

  • Mathematica
    z = 60; s = Sum[k! x^k, {k, 1, z}]; p = 1 - s - s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A000142 shifted *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x] , 1]  (* A289924 *)

A289927 p-INVERT of A014217 (starting at n=1), where p(S) = 1 - S - S^2.

Original entry on oeis.org

1, 4, 15, 53, 187, 656, 2301, 8071, 28308, 99293, 348275, 1221603, 4284864, 15029495, 52717114, 184909361, 648583888, 2274958177, 7979591823, 27989035739, 98173708464, 344351878525, 1207840857737, 4236595263812, 14860185689435, 52123251095327
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 = GoldenRatio; s = Sum[Floor[r^k] x^k, {k, 1, z}]; p = 1 - s - s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A014217 shifted *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x] , 1]  (* A289927 *)

Formula

Conjectures from Colin Barker, Aug 15 2017: (Start)
G.f.: (1 - x^2 + x^3)*(1 + x - x^3) / (1 - 3*x - 4*x^2 + 7*x^3 + 5*x^4 - 7*x^5 - 4*x^6 + 3*x^7 + x^8).
a(n) = 3*a(n-1) + 4*a(n-2) - 7*a(n-3) - 5*a(n-4) + 7*a(n-5) + 4*a(n-6) - 3*a(n-7) - a(n-8) for n>7.
(End)

A289928 p-INVERT of (1,2,3,5,7,11,13,...); i.e., 1 and the primes (A008578), where p(S) = 1 - S - S^2.

Original entry on oeis.org

1, 4, 14, 48, 162, 547, 1842, 6206, 20906, 70438, 237326, 799629, 2694199, 9077599, 30585239, 103051135, 347211149, 1169861760, 3941626163, 13280557904, 44746308037, 150764154490, 507971076799, 1711511703373, 5766612400708, 19429501132982, 65464000013233
Offset: 0

Views

Author

Clark Kimberling, Aug 15 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; s = x + Sum[Prime[k] x^(k + 1), {k, 1, z}]; p = 1 - s - s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A008578 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x] , 1] (* A289928 *)

A289973 p-INVERT of the lower Wythoff sequence (A000201), where p(S) = 1 - S.

Original entry on oeis.org

1, 4, 11, 33, 96, 280, 818, 2387, 6970, 20347, 59401, 173414, 506261, 1477968, 4314748, 12596384, 36773617, 107356118, 313413177, 914971789, 2671149257, 7798096555, 22765597881, 66461404174, 194026015382, 566435438933, 1653639620681, 4827600476829
Offset: 0

Views

Author

Clark Kimberling, Aug 15 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 = GoldenRatio; s = Sum[Floor[k*r] x^k, {k, 1, z}]; p = 1 - s;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A000201 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x] , 1]  (* A289973 *)

A289974 p-INVERT of the upper Wythoff sequence (A001950), where p(S) = 1 - S.

Original entry on oeis.org

2, 9, 35, 139, 549, 2169, 8571, 33866, 133817, 528755, 2089288, 8255476, 32620147, 128893113, 509299806, 2012413902, 7951720511, 31419907712, 124150565816, 490560415825, 1938368302977, 7659141579267, 30263830481105, 119582517950630, 472510530626342
Offset: 0

Views

Author

Clark Kimberling, Aug 15 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;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A001950 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x] , 1]  (* A289974 *)

A290996 p-INVERT of (1,1,1,1,1,...), where p(S) = 1 - S - S^4.

Original entry on oeis.org

1, 2, 4, 9, 22, 55, 136, 330, 789, 1872, 4433, 10510, 24968, 59409, 141470, 336935, 802340, 1910166, 4546845, 10822176, 25758097, 61308650, 145928764, 347350473, 826795942, 1968018151, 4684451824, 11150316882, 26540849109, 63174538224, 150372815489
Offset: 0

Views

Author

Clark Kimberling, Aug 22 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 A291000 for a guide to related sequences.

Crossrefs

Programs

  • Magma
    I:=[1,2,4,9]; [n le 4 select I[n] else 5*Self(n-1) -9*Self(n-2) +7*Self(n-3) -Self(n-4): n in [1..51]]; // G. C. Greubel, Apr 13 2023
    
  • Mathematica
    z = 60; s = x/(1-x); p = 1 -s -s^4;
    Drop[CoefficientList[Series[s, {x,0,z}], x], 1]  (* A000012 *)
    Drop[CoefficientList[Series[1/p, {x,0,z}], x], 1]  (* A290996 *)
    LinearRecurrence[{5,-9,7,-1}, {1,2,4,9}, 60] (* G. C. Greubel, Apr 13 2023 *)
  • PARI
    Vec((1 - 3*x + 3*x^2) / (1 - 5*x + 9*x^2 - 7*x^3 + x^4) + O(x^50)) \\ Colin Barker, Aug 22 2017
    
  • SageMath
    @CachedFunction
    def a(n): # a = A290996
        if(n<4): return (1,2,4,9)[n]
        else: return 5*a(n-1) - 9*a(n-2) + 7*a(n-3) - a(n-4)
    [a(n) for n in range(61)] # G. C. Greubel, Apr 13 2023

Formula

a(n) = 5*a(n-1) - 9*a(n-2) + 7*a(n-3) - a(n-4) for n >= 4.
G.f.: (1 - 3*x + 3*x^2) / (1 - 5*x + 9*x^2 - 7*x^3 + x^4). - Colin Barker, Aug 22 2017

A290999 p-INVERT of (1,1,1,1,1,...), where p(S) = 1 - 6*S^2.

Original entry on oeis.org

0, 6, 12, 54, 168, 606, 2052, 7134, 24528, 84726, 292092, 1007814, 3476088, 11991246, 41362932, 142682094, 492178848, 1697768166, 5856430572, 20201701974, 69685556808, 240379623486, 829187031012, 2860272179454, 9866479513968, 34034319925206, 117401037420252
Offset: 0

Views

Author

Clark Kimberling, Aug 22 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 A291000 for a guide to related sequences.

Crossrefs

Programs

  • Magma
    [n le 2 select 6*(n-1) else 2*Self(n-1) +5*Self(n-2): n in [1..41]]; // G. C. Greubel, Apr 25 2023
    
  • Mathematica
    z = 60; s = x/(1 - x); p = 1 - s^6;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A000012 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A290999 *)
    LinearRecurrence[{2,5},{0,6},30] (* Harvey P. Dale, Mar 25 2018 *)
  • SageMath
    A290999=BinaryRecurrenceSequence(2,5,0,6)
    [A290999(n) for n in range(41)] # G. C. Greubel, Apr 25 2023

Formula

G.f.: 6*x/(1 - 2*x - 5*x^2).
a(n) = 2*a(n-1) + 5*a(n-2) for n >= 3.
a(n) = 6*A002532(n).
a(n) = sqrt(3/2)*((1+sqrt(6))^n - (1-sqrt(6))^n). - Colin Barker, Aug 23 2017

A291001 p-INVERT of (1,1,1,1,1,...), where p(S) = 1 - 8*S^2.

Original entry on oeis.org

0, 8, 16, 88, 288, 1192, 4400, 17144, 65088, 250184, 955984, 3663256, 14018400, 53679592, 205487984, 786733112, 3011882112, 11530896008, 44144966800, 169006205656, 647027178912, 2477097797416, 9483385847216, 36306456276344, 138996613483200, 532138420900808
Offset: 0

Views

Author

Clark Kimberling, Aug 22 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 A291000 for a guide to related sequences.

Crossrefs

Programs

  • Magma
    [n le 2 select 8*(n-1) else 2*Self(n-1) +7*Self(n-2): n in [1..41]]; // G. C. Greubel, Apr 25 2023
    
  • Mathematica
    z = 60; s = x/(1 - x); p = 1 - s^8;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A000012 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291001 *)
    LinearRecurrence[{2,7}, {0,8}, 41] (* G. C. Greubel, Apr 25 2023 *)
  • SageMath
    A291001=BinaryRecurrenceSequence(2,7,0,8)
    [A291001(n) for n in range(41)] # G. C. Greubel, Apr 25 2023

Formula

G.f.: 8*x/(1 - 2*x - 7*x^2).
a(n) = 2*a(n-1) + 7*a(n-2) for n >= 3.
a(n) = 8*A015519(n).
a(n) = sqrt(2)*((1+2*sqrt(2))^n - (1-2*sqrt(2))^n). - Colin Barker, Aug 23 2017

A291002 p-INVERT of (1,1,1,1,1,...), where p(S) = (1 - S)*(1 - 2*S)*(1 - 3*S).

Original entry on oeis.org

6, 31, 146, 652, 2816, 11896, 49496, 203752, 832376, 3381736, 13683896, 55206952, 222242936, 893219176, 3585623096, 14380739752, 57637717496, 230895178216, 924613703096, 3701553914152, 14815513224056, 59289946122856, 237243465219896, 949224905162152
Offset: 0

Views

Author

Clark Kimberling, Aug 22 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 A291000 for a guide to related sequences.

Crossrefs

Programs

  • Magma
    [(2^n-16*3^n+27*4^n)/2: n in [0..40]]; // G. C. Greubel, Apr 27 2023
    
  • Mathematica
    z = 60; s = x/(1-x); p = (1-s)*(1-2*s)*(1-3*s);
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A000012 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291002 *)
    LinearRecurrence[{9,-26,24}, {6,31,146}, 41] (* G. C. Greubel, Apr 27 2023 *)
  • SageMath
    [(2^n-16*3^n+27*4^n)/2 for n in range(41)] # G. C. Greubel, Apr 27 2023

Formula

G.f.: (6 - 23*x + 23*x^2)/(1 - 9*x + 26*x^2 - 24*x^3).
a(n) = 9*a(n-1) - 26*a(n-2) + 24*a(n-3) for n >= 4.
a(n) = (2^n - 16*3^n + 27*4^n) / 2. - Colin Barker, Aug 23 2017
E.g.f.: (1/2)*(exp(2*x) - 16*exp(3*x) + 27*exp(4*x)). - G. C. Greubel, Apr 27 2023
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