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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

Table of n, a(n) for n=0..16.

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 A206820

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 October 17 20:01 EDT 2019. Contains 328128 sequences. (Running on oeis4.)