OFFSET
0,2
LINKS
FORMULA
a(n)=2*a(n-1)+a(n-1)+7; a(0)=1, a(1)=9.
a(0)=1, a(1)=9, a(2)=26, a(n)=3*a(n-1)-a(n-2)-a(n-3). - Harvey P. Dale, May 01 2013
EXAMPLE
a(n)=[ {(8+(9/2)*sqrt(2))(1+sqrt(2))^n -(8-(9/2)*sqrt(2))(1-sqrt(2))^n}/ 2*sqrt(2) ]-7/2.
MATHEMATICA
Table[6*Fibonacci[n, 2] + Fibonacci[n+1, 2], {n, 0, 22}] // Accumulate (* Jean-François Alcover, Mar 25 2013 *)
Accumulate[LinearRecurrence[{2, 1}, {1, 8}, 40]] (* or *) LinearRecurrence[ {3, -1, -1}, {1, 9, 26}, 40] (* Harvey P. Dale, May 01 2013 *)
CROSSREFS
KEYWORD
easy,nice,nonn
AUTHOR
EXTENSIONS
More terms from Harvey P. Dale, May 01 2013
STATUS
approved