OFFSET
0,3
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,1).
FORMULA
G.f.: x*(1 + 2*x + 3*x^2 + 3*x^3 + 2*x^4 + x^5)/(1 - x^7).
a(n) = (1/2) * Sum_{i=1..2n} (-1)^floor((i-1)/7).
a(n) = a(n-7) for n > 6.
a(n) = A279313(2n)/2.
a(n) = -m*(m^5 - 21*m^4 + 160*m^3 - 525*m^2 + 739*m - 714)/360 where m = n mod 7. - Luce ETIENNE, Nov 18 2018
MAPLE
a:=n->[0, 1, 2, 3, 3, 2, 1][(n mod 7)+1]: seq(a(n), n=0..300);
MATHEMATICA
CoefficientList[Series[x*(1 + 2*x + 3*x^2 + 3*x^3 + 2*x^4 + x^5)/(1 - x^7), {x, 0, 100}], x]
PadRight[{}, 120, {0, 1, 2, 3, 3, 2, 1}] (* Vincenzo Librandi, Dec 10 2016 *)
PROG
(Magma) &cat[[0, 1, 2, 3, 3, 2, 1]: n in [0..10]];
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wesley Ivan Hurt, Dec 09 2016
STATUS
approved