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 A144750 A098777 mod 9. 2
 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 (list; graph; refs; listen; history; text; internal format)
 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

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Last modified December 8 18:37 EST 2019. Contains 329865 sequences. (Running on oeis4.)