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 A083862 Main diagonal of array A083857. 2
 0, 1, 3, 10, 39, 171, 819, 4229, 23247, 135088, 824163, 5255361, 34876647, 240130801, 1710323667, 12572548582, 95183606559, 740843916471, 5918533467075, 48463830575837, 406239439253175, 3481899731310196 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Table of n, a(n) for n=0..21. FORMULA a(n) = (((3 + sqrt(4*n + 1))/2)^n - ((3 - sqrt(4*n + 1))/2)^n)/sqrt(4*n + 1). MAPLE T := proc(n, k) local v; option remember; if 0 <= n and k = 0 then v := 0; end if; if 0 <= n and k = 1 then v := 1; end if; if 0 <= n and 2 <= k then v := 3*T(n, k - 1) + (n - 2)*T(n, k - 2); end if; v; end proc; seq(T(n, n), n = 0 .. 40); # Petros Hadjicostas, Dec 25 2019 CROSSREFS Cf. A083857, A083859, A083863. Sequence in context: A245378 A350915 A221585 * A205543 A137590 A352174 Adjacent sequences: A083859 A083860 A083861 * A083863 A083864 A083865 KEYWORD easy,nonn AUTHOR Paul Barry, May 06 2003 STATUS approved

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Last modified September 27 20:41 EDT 2023. Contains 365714 sequences. (Running on oeis4.)