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.

Showing 1-2 of 2 results.

A089075 A nonsense sequence.

Original entry on oeis.org

-1, 1, -1, 2, -2, 4, -4, 7, -7, 12, -12, 22, -21, 39, -39, 68, -70, 119, -127, 210, -229, 369, -413, 649, -742, 1143, -1334, 2017, -2393, 3561, -4289, 6293, -7680, 11129, -13739, 19696, -24559, 34879, -43871, 61801, -78324, 109555, -139764, 194291, -249295, 344694, -444496, 611723, -792285
Offset: 1

Views

Author

Roger L. Bagula, Dec 04 2003

Keywords

Links

Crossrefs

Cf. A089074, A089076, A089077.

Programs

  • Mathematica
    (* k is a root of x^4 - x^3 - 1: *)
k=1.38027756909761411567330169182273187781662670155876302541177133121124957411;
q=k^2-k-1/k-1/k^2;
m0={{0, 1, 0, 0}, {0, 0, 1, 0}, {0, 0, 0, 1}, {1, 1, 1, q}};
m[n_]=MatrixPower[m0, n];
Table[Floor[Re[m[n][[4, 4]]]], {n, 1, 1000}]

Extensions

Edited by G. C. Greubel, Feb 19 2021

A089076 Expansion of -x - x^3*(2 -2*x^4 +x^5)/((1-x^2)*(1+x+x^4)).

Original entry on oeis.org

-1, 0, -2, 2, -4, 4, -6, 7, -11, 14, -20, 26, -37, 50, -70, 95, -132, 181, -251, 345, -477, 657, -908, 1252, -1729, 2385, -3293, 4544, -6273, 8657, -11950, 16493, -22766, 31422, -43372, 59864, -82630, 114051, -157423, 217286, -299916, 413966, -571389, 788674, -1088590, 1502555, -2073944, 2862617
Offset: 1

Views

Author

Roger L. Bagula, Dec 04 2003

Keywords

Links

Crossrefs

Cf. A089074, A089075, A089077.

Programs

  • Magma
    R:=PowerSeriesRing(Integers(), 50);
Coefficients(R!( -x -x^3*(2-2*x^4+x^5)/((1-x^2)*(1+x-x^4)) )); // G. C. Greubel, Feb 19 2021
  • Mathematica
    Rest@CoefficientList[Series[-x -x^3*(2-2*x^4+x^5)/((1-x^2)*(1+x-x^4)), {x,0,50}], x] (* G. C. Greubel, Feb 19 2021 *)
LinearRecurrence[{-1,1,1,1,0,-1},{-1,0,-2,2,-4,4,-6,7},50] (* Harvey P. Dale, Aug 11 2021 *)
  • Sage
    def A089076_list(prec):
    P. = PowerSeriesRing(ZZ, prec)
    return P( -x -x^3*(2-2*x^4+x^5)/((1-x^2)*(1+x-x^4)) ).list()
a=A089076_list(51); a[1:] # G. C. Greubel, Feb 19 2021

Formula

G.f.: -x - x^3*(2 -2*x^4 +x^5)/((1-x^2)*(1+x+x^4)).

Extensions

Edited by G. C. Greubel, Feb 19 2021
Showing 1-2 of 2 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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