OFFSET
0,2
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
"Marsland", Reddit discussion
FORMULA
a(0) = 1;
a(1) = 3;
a(2) = 7;
a(2k+1) = (140 2^(3k) + 318 2^(2k) + 60 2^(k) - 48 + 16 (-1)^(k)) / 144, for k > 0;
a(2k) = (50 2^(3k) + 147 2^(2k) + 60 2^(k) - 48 + 16 (-1)^(k)) / 144, for k > 1.
Empirical g.f.: -(16*x^11 +8*x^10 +14*x^9 -7*x^8 -33*x^7 -8*x^6 -13*x^5 -13*x^4 +16*x^3 +9*x^2 -2*x -1) / ((x -1)*(2*x -1)*(2*x +1)*(x^2 +1)*(2*x^2 -1)*(8*x^2 -1)). - Colin Barker, Nov 14 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Robin Houston, Nov 04 2014
STATUS
approved