login
A106707
a(n) = -A001353(n).
5
0, -1, -4, -15, -56, -209, -780, -2911, -10864, -40545, -151316, -564719, -2107560, -7865521, -29354524, -109552575, -408855776, -1525870529, -5694626340, -21252634831, -79315912984, -296011017105, -1104728155436, -4122901604639, -15386878263120, -57424611447841
OFFSET
0,3
FORMULA
G.f.: -x/(1-4*x+x^2).
a(n) = 4*a(n-1) - a(n-2); a(0)=0, a(1)=-1.
MAPLE
a[0]:=0: a[1]:=-1: for n from 2 to 27 do a[n]:=4*a[n-1]-a[n-2] od: seq(a[n], n=0..27);
MATHEMATICA
LinearRecurrence[{4, -1}, {0, -1}, 30] (* Harvey P. Dale, Nov 01 2019 *)
PROG
(PARI) x='x+O('x^30); Vec(-x/(1-4*x+x^2)) \\ G. C. Greubel, Feb 05 2018
(Magma) I:=[0, -1]; [n le 2 select I[n] else 4*Self(n-1) - Self(n-2): n in [1..30]]; // G. C. Greubel, Feb 05 2018
CROSSREFS
Sequence in context: A191606 A242495 A221859 * A125905 A195503 A001353
KEYWORD
sign,easy,less
AUTHOR
Roger L. Bagula, May 30 2005
EXTENSIONS
Edited by N. J. A. Sloane, Apr 30 2006
New name from Joerg Arndt, Sep 22 2023
STATUS
approved