OFFSET
1,3
LINKS
Index entries for linear recurrences with constant coefficients, signature (1,0,4,-4).
FORMULA
a(n) = Sum_{i=1..n} A006431(i).
G.f.: -x^2*(36*x^13 +28*x^12 +32*x^11 +21*x^10 +17*x^9 +14*x^8 +13*x^7 +12*x^6 +5*x^5 +2*x^4 -x^3 -3*x^2 -2*x -1) / ((x -1)*(4*x^3 -1)). - Colin Barker, Apr 20 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Jonathan Vos Post, May 27 2010
STATUS
approved