OFFSET
1,3
LINKS
FORMULA
G.f.: x*(1-x^4)*(1-x^6)/((1-x)^2*(1-x^3)*(1-x^7)) = x*(1+x+x^2+x^3)*(1+x^3)/((1-x)*(1-x^7)).
a(n) = a(n-7) + 8 = -a(-n) for n > 7.
From Wesley Ivan Hurt, Jul 21 2016: (Start)
a(n) = a(n-1) + a(n-7) - a(n-8) for n > 8.
a(n) = (56*n - 56 + (n mod 7) + ((n+1) mod 7) - 6*((n+2) mod 7) + ((n+3) mod 7) + ((n+4) mod 7) + ((n+5) mod 7) + ((n+6) mod 7))/49.
a(7*k) = 8*k-1, a(7*k-1) = 8*k-2, a(7*k-2) = 8*k-3, a(7*k-3) = 8*k-5, a(7*k-4) = 8*k-6, a(7*k-5) = 8*k-7, a(7*k-6) = 8*k-8. (End)
MAPLE
A047588:=n->8*floor(n/7)+[0, 1, 2, 3, 5, 6, 7][(n mod 7)+1]: seq(A047588(n), n=0..100); # Wesley Ivan Hurt, Jul 21 2016
MATHEMATICA
Complement[Range[100], 4Range[1, 99, 2]] (* Harvey P. Dale, Jan 29 2011 *)
PROG
(PARI) a(n)=n+1+(n-4)\7
(Magma) [n : n in [0..150] | n mod 8 in [0, 1, 2, 3, 5, 6, 7]]; // Wesley Ivan Hurt, Jul 21 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved