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 A184937 a(n) = binomial(2n, n) + binomial(2n-1, n-1) + binomial(2n+1, n). 1
 3, 6, 19, 65, 231, 840, 3102, 11583, 43615, 165308, 629850, 2410226, 9256534, 35659200, 137733660, 533216475, 2068423695, 8037976980, 31285334850, 121941160110, 475898730450 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 LINKS Robert Israel, Table of n, a(n) for n = 0..1661 FORMULA a(n) = A000984(n) + A088218(n) + A088218(n+1). - R. J. Mathar, Feb 04 2011 From Robert Israel, Jan 05 2019: (Start) G.f.: 1/2 - 1/(2*x) + (1+3*x)/(2*x*sqrt(1-4*x)). (6 + 12*n)*a(n) + (7 + n)*a(1 + n) + (-3 - n)*a(n + 2) = 0. (End) MAPLE A184937 := proc(n) binomial(2*n, n)+binomial(2*n-1, n-1)+binomial(2*n+1, n) ; end proc: # R. J. Mathar, Jan 04 2011 MATHEMATICA Table[Binomial[2 n, n] + Binomial[2 n - 1, n - 1] + Binomial[2 n + 1, n], {n, 0, 20}] CROSSREFS Sequence in context: A024607 A186022 A058818 * A215817 A269306 A326317 Adjacent sequences:  A184934 A184935 A184936 * A184938 A184939 A184940 KEYWORD nonn AUTHOR Jon Perry, Feb 02 2011 STATUS approved

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Last modified December 9 04:45 EST 2021. Contains 349626 sequences. (Running on oeis4.)