OFFSET
0,2
LINKS
FORMULA
a(n) = ((7+sqrt(9))^(n+1) - (7-sqrt(9))^(n+1))/6. - Al Hakanson (hawkuu(AT)gmail.com), Jan 07 2009
From Vincenzo Librandi, Mar 18 2011: (Start)
a(n) = 14*a(n-1) - 40*a(n-2), n >= 2.
a(n) = 10*a(n-1) + 4^n = 4*a(n-1) + 10^n, n >= 1. (End)
a(n) = (5*10^n - 2*4^n)/3. - Bruno Berselli, Mar 19 2011
E.g.f.: exp(4*x)*(5*exp(6*x) - 2)/3. - Stefano Spezia, Sep 30 2023
MATHEMATICA
Join[{a=1, b=14}, Table[c=14*b-40*a; a=b; b=c, {n, 60}]] (* Vladimir Joseph Stephan Orlovsky, Feb 01 2011 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved