OFFSET
0,2
LINKS
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
KEYWORD
easy,nonn
AUTHOR
Mario Catalani (mario.catalani(AT)unito.it), Jul 22 2004
STATUS
approved