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.

A291017 p-INVERT of (1,1,1,1,1,...), where p(S) = 1 - 5 S + S^2.

Original entry on oeis.org

5, 29, 168, 973, 5635, 32634, 188993, 1094513, 6338640, 36708889, 212591743, 1231179978, 7130117645, 41292563669, 239137122168, 1384911909493, 8020423511275, 46448581212474, 268997103908393, 1557839658871433, 9021897884741280, 52248407581088929
Offset: 0

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Author

Clark Kimberling, Aug 23 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 A291000 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(1 - x); p = 1 - 5 s + s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A000012 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291017 *)

Formula

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