A144750 A098777 mod 9.

1, 8, 7, 2, 7, 5, 4, 5, 1, 8, 1, 2, 7, 2, 4, 5, 4, 8, 1, 8, 7, 2, 7, 5, 4, 5, 1, 8, 1, 2, 7, 2, 4, 5, 4, 8, 1, 8, 7, 2, 7, 5, 4, 5, 1, 8, 1, 2, 7, 2, 4, 5, 4, 8, 1, 8, 7, 2, 7, 5, 4, 5, 1, 8, 1, 2, 7, 2, 4, 5, 4, 8, 1, 8, 7, 2, 7, 5, 4, 5, 1, 8, 1, 2, 7, 2, 4, 5, 4, 8, 1, 8, 7, 2, 7, 5, 4, 5, 1, 8, 1

Offset

0,2

Links

Muniru A Asiru, Table of n, a(n) for n = 0..1000

R. Bacher and P. Flajolet, Pseudo-factorials, Elliptic Functions and Continued Fractions, arXiv:0901.1379 [math.CA], 2009.

Formula

From Chai Wah Wu, Nov 30 2018: (Start)

a(n) = a(n-2) + a(n-3) - a(n-5) - a(n-6) + a(n-8) for n > 7 (conjectured).

G.f.: (-8*x^7 - 4*x^6 + 3*x^5 + 8*x^4 + 7*x^3 - 6*x^2 - 8*x - 1)/((x - 1)*(x + 1)*(x^6 - x^3 + 1)) (conjectured). (End)

Maple

a:= proc(n) option remember; `if`(n=0, 1, (-1)^n*add(binomial(n-1, k)*a(k)*a(n-1-k), k=0..n-1)) end: seq(modp(a(n), 9), n=0..100); # Muniru A Asiru, Jul 29 2018

Mathematica

b[0] = 1;
b[n_] := b[n] = (-1)^n Sum[Binomial[n-1, k] b[k] b[n-k-1], {k, 0, n-1}];
a[n_] := Mod[b[n], 9]; Table[a[n], {n, 0, 100}] (* Jean-François Alcover, Jul 29 2018 *)

Crossrefs

Sequence in context: A179044 A084254 A255696 * A198928 A155068 A244839

Adjacent sequences: A144747 A144748 A144749 * A144751 A144752 A144753

Keyword

nonn

Author

N. J. A. Sloane, Feb 08 2009

Status

approved