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.

A289925 p-INVERT of the lower Wythoff sequence (A000201), where p(S) = 1 - S - S^2.

Original entry on oeis.org

1, 5, 19, 72, 265, 979, 3618, 13374, 49447, 182807, 675843, 2498594, 9237316, 34150422, 126254366, 466763346, 1725627604, 6379658213, 23585644300, 87196304028, 322365390600, 1191787269208, 4406046481612, 16289186920873, 60221246337260, 222638399818776
Offset: 0

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Author

Clark Kimberling, Aug 14 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 A289780 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; r = GoldenRatio; s = Sum[Floor[k*r] x^k, {k, 1, z}]; p = 1 - s - s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A000201 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x] , 1]  (* A289925 *)