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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A291730 p-INVERT of (1,0,1,0,0,0,0,...), where p(S) = 1 - 2 S - 2 S^2.

Original entry on oeis.org

2, 6, 18, 56, 168, 510, 1544, 4680, 14176, 42952, 130128, 394252, 1194456, 3618840, 10963960, 33217424, 100638528, 304903688, 923764032, 2798719872, 8479257216, 25689531840, 77831351040, 235804967056, 714416256800, 2164460716896, 6557647800096
Offset: 0

Views

Author

Clark Kimberling, Sep 11 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 A291728 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x + x^3; p = 1 - 2 s - 2 s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A154272 *)
    u = Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291730 *)
    u / 2  (* A291731 *)

Formula

G.f.: -((2 (1 + x^2) (1 + x + x^3))/(-1 + 2 x + 2 x^2 + 2 x^3 + 4 x^4 + 2 x^6)).
a(n) = 2*a(n-1) + 2*a(n-2) + 2*a(n-3) + 4*a(n-4) + 2*a(n-6) for n >= 7.

A291732 p-INVERT of (1,0,1,0,0,0,0,...), where p(S) = (1 - 2 S)^2.

Original entry on oeis.org

4, 12, 36, 104, 288, 780, 2080, 5472, 14240, 36736, 94080, 239440, 606144, 1527360, 3833024, 9584768, 23890944, 59380160, 147207168, 364084224, 898569216, 2213388288, 5442392064, 13360097536, 32746992640, 80153705472, 195933828096, 478374127616
Offset: 0

Views

Author

Clark Kimberling, Sep 11 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 A291728 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x + x^3; p = (1 - 2 s)^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A154272 *)
    u = Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291732 *)
    u / 4  (*A291733)

Formula

G.f.: -((4 (1 + x^2) (-1 + x + x^3))/(-1 + 2 x + 2 x^3)^2).
a(n) = 4*a(n-1) - 4*a(n-2) + 4*a(n-3) - 8*a(n-4) - 4*a(n-6) for n >= 7.

A157235 Number of primitive inequivalent oblique sublattices of hexagonal (triangular) lattice of index n (equivalence and symmetry of sublattices are determined using only parent lattice symmetries).

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 0, 0, 1, 2, 1, 2, 1, 3, 2, 2, 2, 5, 2, 4, 3, 5, 3, 4, 4, 6, 5, 6, 4, 10, 4, 6, 6, 8, 6, 10, 5, 9, 7, 8, 6, 14, 6, 10, 10, 11, 7, 12, 8, 14, 10, 12, 8, 17, 10, 12, 11, 14, 9, 20, 9, 15, 14, 14, 12, 22, 10, 16, 14, 22, 11, 20, 11, 18, 18, 18
Offset: 1

Views

Author

N. J. A. Sloane, Feb 25 2009

Keywords

Crossrefs

Cf. A003051 (all sublattices), A003050 (all primitive sublattices), A154272 (primitive sublattices fully inheriting the parent lattice symmetry, inlcuding the orientation of the mirrors), A000086 (primitive rotation-symmetric sublattices, counting mirror images as distinct), A060594 (primitive mirror-symmetric sublattices), A145377 (all sublattices inheriting the parent lattice symmetry), A304182.

Formula

a(n) = A003050(n) - (A000086(n)-A154272(n))/2 - A060594(n). - Andrey Zabolotskiy, Mar 19 2021

Extensions

New name and a(1)=0 prepended by Andrey Zabolotskiy, May 09 2018
Terms a(31) and beyond from Andrey Zabolotskiy, Mar 19 2021

A278105 a(n) = floor(3/n).

Original entry on oeis.org

3, 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, 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, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
Offset: 1

Views

Author

Jason Kimberley, Nov 23 2016

Keywords

Crossrefs

This sequence is (ignoring the trailing zeros) the third row of A010766.

Programs

  • Magma
    [3 div n: n in[1..100]];
  • Mathematica
    Table[Floor[3/n], {n, 105}] (* Michael De Vlieger, Nov 24 2016 *)

Formula

a(n) = A033322(n)+A154272(n). - R. J. Mathar, Jun 21 2025

A291723 p-INVERT of (1,0,1,0,0,0,0,...), where p(S) = 1 - S^3.

Original entry on oeis.org

0, 0, 1, 0, 3, 1, 3, 6, 2, 15, 9, 21, 36, 27, 85, 72, 141, 222, 231, 513, 540, 945, 1422, 1741, 3222, 3876, 6337, 9339, 12447, 20809, 27135, 42546, 62195, 86709, 136866, 187278, 286113, 417303, 595852, 910431, 1281810, 1926984, 2810883, 4064571, 6097464
Offset: 0

Views

Author

Clark Kimberling, Sep 08 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 A291728 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x + x^3; p = 1 - s^3;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A154272 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291723 *)
    LinearRecurrence[{0,0,1,0,3,0,3,0,1},{0,0,1,0,3,1,3,6,2},60] (* Harvey P. Dale, Jun 07 2022 *)

Formula

G.f.: -((x^2 (1 + x^2)^3)/((1 - x + x^2) (-1 + x + x^3) (1 + 2 x + 2 x^2 + x^3 + x^4))).
a(n) = a(n-3) + 3*a(n-5) + 3*a(n-7) + a(n-9) for n >= 10.

A291724 p-INVERT of (1,0,1,0,0,0,0,...), where p(S) = 1 - S^5.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 5, 0, 10, 1, 10, 10, 5, 45, 2, 120, 15, 210, 105, 253, 455, 230, 1365, 310, 3004, 1185, 5030, 4855, 6735, 15506, 8735, 38790, 17655, 77955, 56134, 130030, 178500, 195365, 481750, 327263, 1088225, 761775, 2095350, 2162550, 3593394, 5940325
Offset: 0

Views

Author

Clark Kimberling, Sep 08 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 A291728 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x + x^3; p = 1 - s^5;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A154272 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291724 *)
    LinearRecurrence[{0, 0, 0, 0, 1, 0, 5, 0, 10, 0, 10, 0, 5, 0, 1}, {0, 0, 0, 0, 1, 0, 5, 0, 10, 1, 10, 10, 5, 45, 2}, 50] (* Vincenzo Librandi, Sep 10 2017 *)

Formula

G.f.: -((x^4 (1 + x^2)^5)/((-1 + x + x^3) (1 + x + x^2 + 2 x^3 + 3 x^4 + 3 x^5 + 5 x^6 + 3 x^7 + 6 x^8 + x^9 + 4 x^10 + x^12))).
a(n) = a(n-5) + 5*a(n-7) + 10*a(n-9) + 10*a(n-11) + 5*a(n-13) + a(n-15) for n >= 15.

A291725 p-INVERT of (1,0,1,0,0,0,0,...), where p(S) = (1 - S)^2.

Original entry on oeis.org

2, 3, 6, 11, 18, 30, 50, 81, 130, 208, 330, 520, 816, 1275, 1984, 3077, 4758, 7337, 11286, 17322, 26532, 40563, 61908, 94336, 143540, 218112, 331008, 501749, 759726, 1149159, 1736534, 2621751, 3954826, 5960902, 8977686, 13511461, 20320854, 30542064, 45875998
Offset: 0

Views

Author

Clark Kimberling, Sep 08 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 A291728 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x + x^3; p = (1 - s)^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A154272 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291725 *)
    LinearRecurrence[{2, -1, 2, -2, 0, -1}, {2, 3, 6, 11, 18, 30}, 40] (* Vincenzo Librandi, Sep 10 2017 *)

Formula

G.f.: -(((-1 + x) (1 + x^2) (2 + x + x^2))/(-1 + x + x^3)^2).
a(n) = 2*a(n-1) - a(n-2) + 2*a(n-3) - 2*a(n-4) - a(n-6) for n >= 7.

A291726 p-INVERT of (1,0,1,0,0,0,0,...), where p(S) = (1 - S)^3.

Original entry on oeis.org

3, 6, 13, 27, 51, 94, 171, 303, 527, 906, 1539, 2586, 4308, 7122, 11692, 19077, 30957, 49986, 80349, 128628, 205146, 326058, 516594, 816076, 1285674, 2020380, 3167464, 4954887, 7734993, 12051616, 18743037, 29099781, 45106223, 69810162, 107887629, 166505313
Offset: 0

Views

Author

Clark Kimberling, Sep 08 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 A291728 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x + x^3; p = (1 - s)^3;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A154272 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291726 *)

Formula

G.f.: -(((1 + x^2) (3 - 3 x + x^2 - 3 x^3 + 2 x^4 + x^6))/(-1 + x + x^3)^3).
a(n) = 3*a(n-1) - 3*a(n-2) + 4*a(n-3) - 6*a(n-4) + 3*a(n-5) - 3*a(n-6) + 3*a(n-7) + a(n-9) for n >= 10.

A291727 p-INVERT of (1,0,1,0,0,0,0,...), where p(S) = (1 - S)^4.

Original entry on oeis.org

4, 10, 24, 55, 116, 234, 460, 879, 1640, 3006, 5424, 9650, 16964, 29510, 50852, 86893, 147360, 248198, 415440, 691428, 1144772, 1886270, 3094292, 5055140, 8227084, 13341756, 21564360, 34746331, 55823080, 89439056, 142928424, 227851285, 362396564, 575135150
Offset: 0

Views

Author

Clark Kimberling, Sep 08 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 A291728 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x + x^3; p = (1 - s)^4;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A154272 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291727 *)
    LinearRecurrence[{4,-6,8,-13,12,-10,12,-6,4,-4,0,-1},{4,10,24,55,116,234,460,879,1640,3006,5424,9650},40] (* Harvey P. Dale, Mar 13 2025 *)

Formula

G.f.: -(((-1 + x) (1 + x^2) (2 + x + x^2) (2 - 2 x + x^2 - 2 x^3 + 2 x^4 + x^6))/(-1 + x + x^3)^4).
a(n) = 4*a(n-1) - 6*a(n-2) + 8*a(n-3) - 13*a(n-4) + 12*a(n-5) - 10*a(n-6) + 12*a(n-7) - 6*a(n-8) +4*a(n-9) - 4*a(n-10) - a(n-12) for n >= 13.

A291729 p-INVERT of (1,0,1,0,0,0,0,...), where p(S) = 1 - 2 S - S^2.

Original entry on oeis.org

2, 5, 14, 39, 106, 290, 794, 2173, 5946, 16272, 44530, 121860, 333480, 912597, 2497400, 6834349, 18702782, 51181767, 140063294, 383295214, 1048920220, 2870460125, 7855260268, 21496593296, 58827270844, 160985870984, 440551640160, 1205607339709, 3299247863502
Offset: 0

Views

Author

Clark Kimberling, Sep 11 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 A291728 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x + x^3; p = 1 - 2 s - s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A154272 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291729 *)

Formula

G.f.: (-2 - x - 2 x^2 - 2 x^3 - x^5)/(-1 + 2 x + x^2 + 2 x^3 + 2 x^4 + x^6).
a(n) = 2*a(n-1) + a(n-2) + 2*a(n-3) + 2*a(n-4) + a(n-6) for n >= 7.
Previous Showing 11-20 of 31 results. Next