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.

Previous Showing 31-40 of 48 results. Next

A291242 p-INVERT of (0,1,0,1,0,1,...), where p(S) = 1 - 2 S - S^2 + S^3.

Original entry on oeis.org

2, 5, 13, 35, 91, 241, 631, 1662, 4362, 11470, 30127, 79179, 208023, 546633, 1436257, 3773939, 9916134, 26055432, 68461966, 179888381, 472667065, 1241962303, 3263330095, 8574599917, 22530279167, 59199680826, 155550750026, 408719050346, 1073934109927
Offset: 0

Views

Author

Clark Kimberling, Aug 28 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 A291219 for a guide to related sequences.

Crossrefs

Programs

  • Magma
    I:=[2,5,13,35,91,241]; [n le 6 select I[n] else 2*Self(n-1)+4*Self(n-2)-5*Self(n-3)-4*Self(n-4)+2*Self(n-5)+Self(n-6): n in [1..30]]; // Vincenzo Librandi, Aug 29 2017
  • Mathematica
    z = 60; s = x/(1 - x^2); p = 1 - 2 s - s^2 + s^3;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A000035 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291242 *)
    LinearRecurrence[{2, 4, -5, -4, 2, 1}, {2, 5, 13, 35, 91, 241}, 30] (* Vincenzo Librandi, Aug 29 2017 *)

Formula

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

A291243 p-INVERT of (0,1,0,1,0,1,...), where p(S) = 1 - 3 S + S^2.

Original entry on oeis.org

3, 8, 24, 71, 210, 621, 1836, 5428, 16047, 47440, 140247, 414612, 1225716, 3623579, 10712370, 31668929, 93622704, 276776352, 818232603, 2418937120, 7151092203, 21140739568, 62498266944, 184763326671, 546214936050, 1614772594421, 4773744472356, 14112597876668
Offset: 0

Views

Author

Clark Kimberling, Aug 28 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 A291219 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(1 - x^2); p = 1 - 3 s - s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A000035 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291243 *)

Formula

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

A291244 p-INVERT of (0,1,0,1,0,1,...), where p(S) = 1 - 4 S + S^2.

Original entry on oeis.org

4, 15, 60, 239, 952, 3792, 15104, 60161, 239628, 954465, 3801740, 15142752, 60315260, 240242367, 956911980, 3811486495, 15181573232, 60469889136, 240858271816, 959365196977, 3821257929948, 15220493940369, 60624914631700, 241475755550400, 961824703141876
Offset: 0

Views

Author

Clark Kimberling, Aug 28 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 A291219 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(1 - x^2); p = 1 - 4 s - s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A000035 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291244 *)

Formula

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

A291245 p-INVERT of (0,1,0,1,0,1,...), where p(S) = 1 - 5 S + S^2.

Original entry on oeis.org

5, 24, 120, 599, 2990, 14925, 74500, 371876, 1856265, 9265776, 46251265, 230868900, 1152410620, 5752399899, 28713814350, 143328549649, 715442152480, 3571217840400, 17826174791885, 88981552487776, 444162405876285, 2217091490069376, 11066885918992400
Offset: 0

Views

Author

Clark Kimberling, Aug 28 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 A291219 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(1 - x^2); p = 1 - 5 s - s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A000035 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291245 *)

Formula

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

A291246 p-INVERT of (0,1,0,1,0,1,...), where p(S) = 1 - 6 S + S^2.

Original entry on oeis.org

6, 35, 210, 1259, 7548, 45252, 271296, 1626481, 9751122, 58460185, 350482050, 2101219272, 12597285450, 75523579487, 452780964690, 2714524435655, 16274188816248, 97567447965516, 584938949030724, 3506841484816717, 21024308981321682, 126045494230596949
Offset: 0

Views

Author

Clark Kimberling, Aug 28 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 A291219 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(1 - x^2); p = 1 - 6 s - s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A000035 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291246 *)

Formula

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

A291247 p-INVERT of (0,1,0,1,0,1,...), where p(S) = 1 - S - S^2 - S^3 + S^4.

Original entry on oeis.org

1, 2, 5, 10, 24, 49, 112, 238, 526, 1142, 2491, 5442, 11842, 25873, 56344, 122975, 268042, 584633, 1274820, 2779895, 6062306, 13219186, 28827703, 62861754, 137082358, 298927682, 651861824, 1421488867, 3099781932, 6759580078, 14740333285, 32143687954
Offset: 0

Views

Author

Clark Kimberling, Aug 29 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 A291219 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(1 - x^2); p = 1 - s - s^2 - s^3 + s^4;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A000035 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291247 *)

Formula

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

A291248 p-INVERT of (0,1,0,1,0,1,...), where p(S) = 1 - S - S^2 - S^3 - S^4 + S^5.

Original entry on oeis.org

1, 2, 5, 12, 27, 65, 146, 346, 788, 1845, 4239, 9865, 22758, 52818, 122072, 282954, 654528, 1516221, 3508817, 8125763, 18808494, 43550500, 100815652, 233418699, 540371471, 1251079052, 2896357943, 6705591388, 15524220275, 35941069252, 83208225215
Offset: 0

Views

Author

Clark Kimberling, Aug 29 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 A291219 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(1 - x^2); p = 1 - s - s^2 - s^3 - s^4 + s^5;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A000035 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291248 *)

Formula

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

A291249 p-INVERT of (0,1,0,1,0,1,...), where p(S) = 1 - S - S^2 - S^3 + S^4 + S^5.

Original entry on oeis.org

1, 2, 5, 10, 23, 47, 102, 214, 452, 955, 2003, 4223, 8854, 18610, 39032, 81896, 171752, 360103, 754985, 1582497, 3316978, 6951684, 14568692, 30530311, 63977107, 134063288, 280920507, 588643384, 1233430247, 2584481968, 5415381139, 11347029572, 23775710791
Offset: 0

Views

Author

Clark Kimberling, Aug 29 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 A291219 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(1 - x^2); p = 1 - s - s^2 - s^3 + s^4 + s^5;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A000035 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291249 *)
    LinearRecurrence[{1,6,-3,-14,3,14,-3,-6,1,1},{1,2,5,10,23,47,102,214,452,955},40] (* Harvey P. Dale, Jul 21 2018 *)

Formula

G.f.: -((1 + x - 3 x^2 - 4 x^3 + 3 x^4 + 4 x^5 - 3 x^6 - x^7 + x^8)/((-1 + x + x^2) (1 + x - x^2 - x^3 + x^4) (1 - x - 3 x^2 + x^3 + x^4))).
a(n) = a(n-1) + 6*a(n-2) - 3*a(n-3) - 14*a(n-4) + 3*a(n-5) + 14*a(n-6) - 3*a(n-7) - 6*a(n-8) + a(n-9) + a(n-10) for n >= 11.

A291250 p-INVERT of (0,1,0,1,0,1,...), where p(S) = 1 - S - 2 S^2 + 2 S^3.

Original entry on oeis.org

1, 3, 4, 13, 17, 52, 69, 203, 272, 781, 1053, 2976, 4029, 11267, 15296, 42469, 57765, 159596, 217361, 598499, 815860, 2241165, 3057025, 8383872, 11440897, 31340691, 42781588, 117100285, 159881873, 437378260, 597260133, 1633244795, 2230504928, 6097779229
Offset: 0

Views

Author

Clark Kimberling, Aug 29 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 A291219 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(1 - x^2); p = 1 - s - 2 s^2 + 2 s^3;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A000035 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291250 *)
    LinearRecurrence[{1,5,-4,-5,1,1},{1,3,4,13,17,52},40] (* Harvey P. Dale, May 13 2019 *)

Formula

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

A291251 p-INVERT of (0,1,0,1,0,1,...), where p(S) = 1 - 3 S + 2 S^3.

Original entry on oeis.org

0, 3, -2, 15, -18, 76, -126, 405, -802, 2241, -4884, 12696, -29100, 72903, -171490, 421683, -1005030, 2448356, -5873706, 14243001, -34280258, 82936965, -199930344, 483172656, -1165648152, 2815517835, -6794932418, 16408304343, -39606671610, 95629756540
Offset: 0

Views

Author

Clark Kimberling, Aug 29 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).
Putting s = (0, -1, 0, -1, 0, -1, ...) gives (|a(n)|). For given s, it would be of interest to know conditions on p that imply that t(s) has terms that are all positive (or all nonnegative, or strictly increasing, or alternating, as in the present case.)
See A291219 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(1 - x^2); p = 1 - 3 s^2 + 2 s^3;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A000035 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291251 *)

Formula

G.f.: (x (-3 + 2 x + 3 x^2))/((-1 - 2 x + x^2) (-1 + x + x^2)^2).
a(n) = 6*a(n-2) - 2*a(n-3) - 6*a(n-4) + a(n-6) for n >= 7.
Previous Showing 31-40 of 48 results. Next