cp's OEIS Frontend

A144750 A098777 mod 9.

%I A144750 #15 Dec 01 2018 04:38:59
%S A144750 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,
%T A144750 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,
%U A144750 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
%N A144750 A098777 mod 9.
%H A144750 Muniru A Asiru, <a href="/A144750/b144750.txt">Table of n, a(n) for n = 0..1000</a>
%H A144750 R. Bacher and P. Flajolet, <a href="https://arxiv.org/abs/0901.1379">Pseudo-factorials, Elliptic Functions and Continued Fractions</a>, arXiv:0901.1379 [math.CA], 2009.
%F A144750 From _Chai Wah Wu_, Nov 30 2018: (Start)
%F A144750 a(n) = a(n-2) + a(n-3) - a(n-5) - a(n-6) + a(n-8) for n > 7 (conjectured).
%F A144750 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)
%p A144750 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
%t A144750 b[0] = 1;
%t A144750 b[n_] := b[n] = (-1)^n Sum[Binomial[n-1, k] b[k] b[n-k-1], {k, 0, n-1}];
%t A144750 a[n_] := Mod[b[n], 9]; Table[a[n], {n, 0, 100}] (* _Jean-François Alcover_, Jul 29 2018 *)
%K A144750 nonn
%O A144750 0,2
%A A144750 _N. J. A. Sloane_, Feb 08 2009