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 A046885 Row sums of triangle A046658. 1
 1, 4, 18, 85, 411, 2013, 9933, 49236, 244750, 1218888, 6077644, 30329434, 151439158, 756452890, 3779590010, 18888255205, 94405918355, 471899946985, 2359022096225, 11793343217935, 58960151969255, 294776293579255 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS FORMULA a(n) = 2*5^(n-1) - A046714(n-1) = (A046748(n) - 5^(n-1))/2; G.f.: x*(2-c(x))/(1-5*x), c(x): = g.f. for A000108 (Catalan numbers). i) Inhomogeneous recursion: a(n) = 5*a(n-1) - C(n-1), n >= 2, a(1)=1; C(n)=A000108(n) (Catalan). ii) Homogeneous recursion: a(n) = (3*(3*n-2)/n)*a(n-1) - (10*(2*n-3)/n)*a(n-2), n >= 3, a(1)=1, a(2)=4. CROSSREFS Cf. A046658, A046714, A046748, A000108. Sequence in context: A185132 A085923 A110166 * A055834 A079567 A030278 Adjacent sequences:  A046882 A046883 A046884 * A046886 A046887 A046888 KEYWORD easy,nonn AUTHOR STATUS approved

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