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 A082987 a(n)=sum(k=0,n,3^k*F(k)) where F(k) is the k-th Fibonacci number. 0
 0, 3, 12, 66, 309, 1524, 7356, 35787, 173568, 842790, 4090485, 19856568, 96384072, 467861331, 2271040644, 11023873914, 53510987541, 259747827852, 1260842371428, 6120257564955, 29708354037720, 144207380197758 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Index entries for linear recurrences with constant coefficients, signature (4,6,-9). FORMULA a(0)=0, a(1)=3, a(2)=12, a(n)=4a(n-1)+6a(n-2)-9a(n-3). G.f.: 3*x^2 / ((x-1)*(9*x^2+3*x-1)). - Colin Barker, Jun 26 2013 MATHEMATICA LinearRecurrence[{4, 6, -9}, {0, 3, 12}, 30] (* Harvey P. Dale, Feb 03 2019 *) PROG (PARI) a(n)=if(n<0, 0, sum(k=0, n-1, fibonacci(k)*3^k)) CROSSREFS Cf. A014334. Sequence in context: A144297 A007017 A183273 * A086836 A074513 A290147 Adjacent sequences:  A082984 A082985 A082986 * A082988 A082989 A082990 KEYWORD nonn,easy AUTHOR Benoit Cloitre, May 29 2003 STATUS approved

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Last modified September 27 12:51 EDT 2021. Contains 347688 sequences. (Running on oeis4.)