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 61-64 of 64 results.

A291182 p-INVERT of the positive integers, where p(S) = 1 - 3*S + 2*S^2.

Original entry on oeis.org

3, 13, 52, 203, 781, 2976, 11267, 42469, 159596, 598499, 2241165, 8383872, 31340691, 117100285, 437378260, 1633244795, 6097779229, 22763575008, 84971451155, 317161317781, 1183776154124, 4418211213011, 16489770106653, 61542705525504, 229685859522339
Offset: 0

Views

Author

Clark Kimberling, Aug 19 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 A290890 for a guide to related sequences.

Crossrefs

Programs

  • Magma
    I:=[3,13,52,203]; [n le 4 select I[n] else 7*Self(n-1)-14*Self(n-2)+7*Self(n-3)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Aug 20 2017
  • Mathematica
    z = 60; s = x/(1 - x)^2; p = 1 - 3 s + 2 s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A000027 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291182 *)
    LinearRecurrence[{7, -14, 7, -1}, {3, 13, 52, 203}, 40] (* Vincenzo Librandi, Aug 20 2017 *)

Formula

G.f.: (3 - 8 x + 3 x^2)/(1 - 7 x + 14 x^2 - 7 x^3 + x^4).
a(n) = 7*a(n-1) - 14*a(n-2) + 7*a(n-3) - a(n-4).

A291183 p-INVERT of the positive integers, where p(S) = 1 - 4*S + 2*S^2.

Original entry on oeis.org

4, 22, 116, 608, 3180, 16618, 86812, 453440, 2368292, 12369174, 64601428, 337397536, 1762142540, 9203221994, 48066074172, 251036784256, 1311100720708, 6847542588950, 35762957380148, 186780746599392, 975507894703660, 5094827328491242, 26608975328086364
Offset: 0

Views

Author

Clark Kimberling, Aug 19 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 A290890 for a guide to related sequences.

Crossrefs

Programs

  • Magma
    I:=[4,22,116,608]; [n le 4 select I[n] else 8*Self(n-1)-16*Self(n-2)+8*Self(n-3)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Aug 20 2017
  • Mathematica
    z = 60; s = x/(1 - x)^2; p = 1 - 4 s + 2 s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A000027 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291183 *)
    LinearRecurrence[{8, -16, 8, -1}, {4, 22, 116, 608}, 40] (* Vincenzo Librandi, Aug 20 2017 *)

Formula

G.f.: (2 (2 - 5 x + 2 x^2))/(1 - 8 x + 16 x^2 - 8 x^3 + x^4).
a(n) = 8*a(n-1) - 16*a(n-2) + 8*a(n-3) - a(n-4).

A291184 p-INVERT of the positive integers, where p(S) = 1 - 4*S + 3*S^2.

Original entry on oeis.org

4, 21, 104, 507, 2452, 11808, 56732, 272229, 1305400, 6257355, 29988140, 143701056, 688563508, 3299237877, 15807943688, 75741312603, 362900797636, 1738768378464, 8330956025036, 39916050834885, 191249400483544, 916331219497131, 4390407398410844
Offset: 0

Views

Author

Clark Kimberling, Aug 19 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 A290890 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(1 - x)^2; p = 1 - 4 s + 3 s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A000027 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291184 *)
    LinearRecurrence[{8,-17,8,-1},{4,21,104,507},30] (* Harvey P. Dale, Feb 24 2018 *)

Formula

G.f.: (4 - 11 x + 4 x^2)/(1 - 8 x + 17 x^2 - 8 x^3 + x^4).
a(n) = 8*a(n-1) - 17*a(n-2) + 8*a(n-3) - a(n-4).

A291030 p-INVERT of the positive integers, where p(S) = 1 - S - S^2 - S^3 - S^4.

Original entry on oeis.org

1, 4, 15, 56, 208, 767, 2812, 10278, 37530, 137044, 500571, 1828818, 6682264, 24416877, 89218462, 325997507, 1191160160, 4352355633, 15902968338, 58107491971, 212317732888, 775783501558, 2834620130881, 10357363200392, 37844566834330, 138279520124262
Offset: 0

Views

Author

Clark Kimberling, Aug 19 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 A290890 for a guide to related sequences.

Crossrefs

Programs

  • Magma
    I:=[1,4,15,56,208,767,2812,10278]; [n le 8 select I[n] else 9*Self(n-1)-33*Self(n-2)+68*Self(n-3)-85*Self(n-4)+68*Self(n-5)-33*Self(n-6)+9*Self(n-7)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Aug 20 2017
  • 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] (* A000027 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291030 *)
    LinearRecurrence[{9, -33, 68, -85, 68, -33, 9, -1}, {1, 4, 15, 56, 208, 767, 2812, 10278}, 40] (* Vincenzo Librandi, Aug 20 2017 *)

Formula

G.f.: (1 - 5 x + 12 x^2 - 15 x^3 + 12 x^4 - 5 x^5 + x^6)/(1 - 9 x + 33 x^2 - 68 x^3 + 85 x^4 - 68 x^5 + 33 x^6 - 9 x^7 + x^8).
a(n) = 9*a(n-1) - 33*a(n-2) + 68*a(n-3) - 85*a(n-4) + 68*a(n-5) - 33*a(n-6) + 9*a(n-7) - a(n-8).
Previous Showing 61-64 of 64 results.