OFFSET
1,1
LINKS
Index entries for linear recurrences with constant coefficients, signature (1,0,0,1,-1).
FORMULA
G.f.: x*(2+x+2*x^2+x^3+x^4) / ( (1+x)*(1+x^2)*(x-1)^2 ). - R. J. Mathar, Dec 04 2011
From Wesley Ivan Hurt, Jun 03 2016: (Start)
a(n) = a(n-1) + a(n-4) - a(n-5) for n>5.
a(n) = (14*n-3-3*i^(2*n)-(1-i)*i^(-n)-(1+i)*i^n)/8 where i=sqrt(-1).
MAPLE
A047331:=n->(14*n-3-3*I^(2*n)-(1-I)*I^(-n)-(1+I)*I^n)/8: seq(A047331(n), n=1..100); # Wesley Ivan Hurt, Jun 03 2016
MATHEMATICA
Table[(14n-3-3*I^(2n)-(1-I)*I^(-n)-(1+I)*I^n)/8, {n, 80}] (* Wesley Ivan Hurt, Jun 03 2016 *)
PROG
(Magma) [n : n in [0..150] | n mod 7 in [2, 3, 5, 6]]; // Wesley Ivan Hurt, Jun 03 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved