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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A290912 a(n) = (1/6)*A290911(n).

Original entry on oeis.org

0, 1, 4, 16, 68, 287, 1208, 5088, 21432, 90273, 380236, 1601584, 6745996, 28414655, 119684720, 504121280, 2123397744, 8943915201, 37672461204, 158679314512, 668369521108, 2815224014047, 11857940853032, 49946562182048, 210378775263272, 886131640451169
Offset: 0

Views

Author

Clark Kimberling, Aug 18 2017

Keywords

Crossrefs

Programs

  • GAP
    a:=[0,1,4,16];; for n in [5..30] do a[n]:=4*a[n-1]+4*a[n-3]-a[n-4]; od; a; # Muniru A Asiru, Sep 12 2018
    
  • Magma
    I:=[0,1,4,16]; [n le 4 select I[n] else 4*Self(n-1)+4*Self(n-3)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Sep 13 2018
  • Maple
    seq(coeff(series(x/(x^4-4*x^3-4*x+1),x,n+1), x, n), n = 0 .. 30); # Muniru A Asiru, Sep 12 2018
  • Mathematica
    z = 60; s = x/(1 - x)^2; p = 1 - 6 s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A000027 *)
    u = Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1] (* A290911 *)
    u/6 (* A290912 *)
    LinearRecurrence[{4,0,4,-1},{0,1,4,16},30] (* Harvey P. Dale, Sep 18 2022 *)
  • PARI
    x='x+O('x^33); concat(0, Vec(x/(1-4*x-4*x^3+x^4))) \\ Altug Alkan, Sep 12 2018
    

Formula

G.f.: x/(1 - 4 x - 4 x^3 + x^4). [Corrected by A.H.M. Smeets, Sep 12 2018]
a(n) = 4*a(n-1) + 4*a(n-3) - a(n-4).
a(n) = (1/6)*A290911(n) for n >= 0.

A290913 p-INVERT of the positive integers, where p(S) = 1 - 7*S^2.

Original entry on oeis.org

0, 7, 28, 119, 532, 2352, 10388, 45913, 202916, 896777, 3963288, 17515680, 77410200, 342112855, 1511961052, 6682082183, 29531331004, 130513137552, 576800248892, 2549157374953, 11265950967908, 49789649104601, 220044376637232, 972481802150208, 4297864230688560
Offset: 0

Views

Author

Clark Kimberling, Aug 18 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 - 7 s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A000027 *)
    u = Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1] (* A290913 *)
    u/7 (* A290914 *)
    LinearRecurrence[{4,1,4,-1},{0,7,28,119},30] (* Harvey P. Dale, Dec 26 2018 *)

Formula

G.f.: (7 x)/(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).
a(n) = 7*A290914(n) for n >= 0.

A290914 a(n) = (1/7)*A290913(n).

Original entry on oeis.org

0, 1, 4, 17, 76, 336, 1484, 6559, 28988, 128111, 566184, 2502240, 11058600, 48873265, 215994436, 954583169, 4218761572, 18644733936, 82400035556, 364165339279, 1609421566844, 7112807014943, 31434910948176, 138925971735744, 613980604384080, 2713475226049825
Offset: 0

Views

Author

Clark Kimberling, Aug 18 2017

Keywords

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(1 - x)^2; p = 1 - 7 s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A000027 *)
    u = Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1] (* A290913 *)
    u/7 (* A290914 *)
    LinearRecurrence[{4,1,4,-1},{0,1,4,17},30] (* Harvey P. Dale, May 05 2019 *)

Formula

G.f.: x/(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).
a(n) = (1/7)*A290913(n) for n >= 0.

A290915 p-INVERT of the positive integers, where p(S) = 1 - 8*S^2.

Original entry on oeis.org

0, 8, 32, 144, 672, 3096, 14272, 65824, 303552, 1399848, 6455520, 29770160, 137287520, 633112632, 2919650688, 13464207936, 62091296128, 286339090504, 1320476135328, 6089483698896, 28082152132128, 129503141377112, 597214328432960, 2754102721315680
Offset: 0

Views

Author

Clark Kimberling, Aug 18 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 - 8 s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A000027 *)
    u = Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1] (* A290915 *)
    u/8 (* A290916 *)

Formula

G.f.: (8 x)/(1 - 4 x - 2 x^2 - 4 x^3 + x^4).
a(n) = 4*a(n-1) + 2*a(n-2) + 4*a(n-3) - a(n-4).
a(n) = 8*A290916(n) for n >= 0.

A290916 a(n) = (1/8)*A290915(n).

Original entry on oeis.org

0, 1, 4, 18, 84, 387, 1784, 8228, 37944, 174981, 806940, 3721270, 17160940, 79139079, 364956336, 1683025992, 7761412016, 35792386313, 165059516916, 761185462362, 3510269016516, 16187892672139, 74651791054120, 344262840164460, 1587596244438120
Offset: 0

Views

Author

Clark Kimberling, Aug 18 2017

Keywords

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(1 - x)^2; p = 1 - 8 s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A000027 *)
    u = Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1] (* A290915 *)
    u/8 (* A290916 *)

Formula

G.f.: x/(1 - 4 x - 2 x^2 - 4 x^3 + x^4).
a(n) = 4*a(n-1) + 2*a(n-2) + 4*a(n-3) - a(n-4).
a(n) = (1/8)*A290915(n) for n >= 0.

A290918 p-INVERT of the positive integers, where p(S) = (1 - S)^3.

Original entry on oeis.org

3, 12, 43, 147, 486, 1566, 4944, 15351, 47009, 142278, 426315, 1266300, 3732705, 10928910, 31806583, 92069229, 265215756, 760621914, 2172669846, 6183333681, 17538237677, 49590486888, 139817553417, 393157465848, 1102792703055, 3086146454592, 8617872504643
Offset: 0

Views

Author

Clark Kimberling, Aug 18 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 - s)^3;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A000027 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A290918 *)

Formula

G.f.: (3 - 15 x + 25 x^2 - 15 x^3 + 3 x^4)/(1 - 3 x + x^2)^3.
a(n) = 9*a(n-1) - 30*a(n-2) + 45*a(n-3) - 30*a(n-4) + 9*a(n-5) - a(n-6).
(a(n)) is the p-INVERT of (1,1,1,1,1...) using p(S) = (1 - S - S^2)^3.

A290923 p-INVERT of the positive integers, where p(S) = 1 - 2*S - 2*S^2.

Original entry on oeis.org

2, 10, 46, 208, 938, 4230, 19078, 86048, 388106, 1750490, 7895302, 35610480, 160615298, 724429270, 3267420814, 14737172032, 66469626002, 299800475370, 1352201455582, 6098885514512, 27508034668634, 124070532153830, 559600027205398, 2523985228499040
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 - 2 s - 2 s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A000027 *)
    u = Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A290923 *)
    u/2   (* A290924 *)

Formula

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

A290924 a(n) = (1/2)*A290923(n).

Original entry on oeis.org

1, 5, 23, 104, 469, 2115, 9539, 43024, 194053, 875245, 3947651, 17805240, 80307649, 362214635, 1633710407, 7368586016, 33234813001, 149900237685, 676100727791, 3049442757256, 13754017334317, 62035266076915, 279800013602699, 1261992614249520, 5692013155802701
Offset: 0

Views

Author

Clark Kimberling, Aug 19 2017

Keywords

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(1 - x)^2; p = 1 - 2 s - 2 s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A000027 *)
    u = Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A290923 *)
    u/2   (* A290924 *)
    LinearRecurrence[{6,-8,6,-1},{1,5,23,104},30] (* Harvey P. Dale, Nov 10 2022 *)

Formula

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

A290992 p-INVERT of (0,0,0,1,2,3,4,5,...), the nonnegative integers A000027 preceded by two zeros, where p(S) = 1 - S - S^2.

Original entry on oeis.org

0, 0, 0, 1, 2, 3, 4, 7, 14, 27, 48, 82, 140, 242, 420, 726, 1250, 2153, 3720, 6446, 11184, 19408, 33676, 58431, 101378, 175861, 304988, 528800, 916714, 1589091, 2754612, 4775074, 8277754, 14350253, 24878304, 43131381, 74777890, 129645147, 224770632
Offset: 0

Views

Author

Clark Kimberling, Aug 21 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
    R:=PowerSeriesRing(Integers(), 60); [0,0,0] cat Coefficients(R!( x^3*(1-2*x+x^2+x^4)/(1-4*x+6*x^2-4*x^3+2*x^5-x^6-x^8) )); // G. C. Greubel, Apr 12 2023
    
  • Mathematica
    z = 60; s = x^4/(1 - x)^2; p = 1 - s - s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* 0,0,0,1,2,3,4,5,... *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A290992 *)
  • PARI
    concat(vector(3), Vec(x^3*(1 - 2*x + x^2 + x^4) / (1 - 4*x + 6*x^2 - 4*x^3 + 2*x^5 - x^6 - x^8) + O(x^50))) \\ Colin Barker, Aug 24 2017
    
  • SageMath
    def f(x): return x^3*(1-2*x+x^2+x^4)/(1-4*x+6*x^2-4*x^3+2*x^5-x^6-x^8)
    def A290992_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P( f(x) ).list()
    A290992_list(60) # G. C. Greubel, Apr 12 2023

Formula

a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - 2*a(n-5) + a(n-6) + a(n-8).
G.f.: x^3*(1 - 2*x + x^2 + x^4) / (1 - 4*x + 6*x^2 - 4*x^3 + 2*x^5 - x^6 - x^8). - Colin Barker, Aug 24 2017

A291033 p-INVERT of the positive integers, where p(S) = 1 - 6*S.

Original entry on oeis.org

6, 48, 378, 2976, 23430, 184464, 1452282, 11433792, 90018054, 708710640, 5579667066, 43928625888, 345849340038, 2722866094416, 21437079415290, 168773769227904, 1328753074407942, 10461250826035632, 82361253533877114, 648428777444981280, 5105068966025973126
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 - 6 s;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A000027 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291033 *)

Formula

G.f.: 6/(1 - 8 x + x^2).
a(n) = 8*a(n-1) - a(n-2).
a(n) = 6*A001090(n) for n >= 1.
Previous Showing 21-30 of 64 results. Next