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 A097068 a(n)=Sum(C(n,2k+1)5^k 3^(2k+1) 7^(n-2k-1), k=0,..,Floor[(n-1)/2]). 0
 0, 3, 42, 576, 7896, 108240, 1483776, 20339904, 278823552, 3822170112, 52395087360, 718242542592, 9845815246848, 134968443285504, 1850174945009664, 25362575456993280, 347675356617867264 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Index entries for linear recurrences with constant coefficients, signature (14, -4). FORMULA a(n)=2^(n-1)F(4n), where F(n) are Fibonacci numbers A000045 a(n)= 14*a(n-1) -4*a(n-2). G.f.: 3*x/(1-14*x+4*x^2). [From R. J. Mathar, Feb 06 2010] MATHEMATICA Table[Sum[Binomial[n, 2k + 1]5^k 3^(2k + 1)7^(n-2k-1), {k, 0, Floor[(n - 1)/2]}], {n, 0, 25}] CROSSREFS Sequence in context: A003770 A173936 A219619 * A269046 A092470 A336572 Adjacent sequences:  A097065 A097066 A097067 * A097069 A097070 A097071 KEYWORD easy,nonn AUTHOR Mario Catalani (mario.catalani(AT)unito.it), Jul 22 2004 STATUS approved

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Last modified April 11 06:40 EDT 2021. Contains 342886 sequences. (Running on oeis4.)