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A192762
Coefficient of x in the reduction by x^2->x+1 of the polynomial p(n,x) defined below in Comments.
5
0, 1, 6, 13, 26, 47, 82, 139, 232, 383, 628, 1025, 1668, 2709, 4394, 7121, 11534, 18675, 30230, 48927, 79180, 128131, 207336, 335493, 542856, 878377, 1421262, 2299669, 3720962, 6020663, 9741658, 15762355, 25504048, 41266439, 66770524
OFFSET
0,3
COMMENTS
The titular polynomial is defined recursively by p(n,x)=x*(n-1,x)+n+4 for n>0, where p(0,x)=1. For discussions of polynomial reduction, see A192232 and A192744.
FORMULA
a(n) = 3*a(n-1)-2*a(n-2)-a(n-3)+a(n-4). G.f.: x*(3*x^2-3*x-1) / ((x-1)^2*(x^2+x-1)). [Colin Barker, Dec 08 2012]
MATHEMATICA
p[0, n_] := 1; p[n_, x_] := x*p[n - 1, x] + n + 4;
Table[Expand[p[n, x]], {n, 0, 7}]
reduce[{p1_, q_, s_, x_}] :=
FixedPoint[(s PolynomialQuotient @@ #1 +
PolynomialRemainder @@ #1 &)[{#1, q, x}] &, p1]
t = Table[reduce[{p[n, x], q, s, x}], {n, 0, z}];
u1 = Table[Coefficient[Part[t, n], x, 0], {n, 1, z}]
(* A022319 *)
u2 = Table[Coefficient[Part[t, n], x, 1], {n, 1, z}]
(* A192762 *)
CROSSREFS
Cf. A192744, A192232, A022319 (first differences).
Sequence in context: A117072 A081395 A343007 * A268721 A183337 A358244
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jul 09 2011
STATUS
approved