OFFSET
3,9
LINKS
J. Riordan, The number of score sequences in tournaments, J. Combin. Theory, 5 (1968), 87-89. [But beware errors.]
EXAMPLE
1;
1 + t + t^2 + t^3 + t^4 + t^5;
t^10 + t^9 + 2*t^8 + 2*t^7 + 3*t^6 + 3*t^5 + 3*t^4 + 2*t^3 + 2*t^2 + t + 1;
...
MAPLE
p := proc(n) option remember; if n = 3 then 1 else (1-t^(2*n-4))*(1-t^(2*n-3))*p(n-1)/((1-t^(n-3))*(1-t^n)); fi; end;
MATHEMATICA
p[3] = 1; p[n_] := p[n] = (1 - t^(2*n-4))*(1 - t^(2*n-3))*p[n-1]/((1 - t^(n-3))*(1 - t^n)) // Simplify; Table[ CoefficientList[ Series[p[n], {t, 0, n^3}], t], {n, 3, 8}] // Flatten (* Jean-François Alcover, Oct 25 2013 *)
CROSSREFS
KEYWORD
nonn,easy,nice,tabf
AUTHOR
EXTENSIONS
Keyword tabf by Michel Marcus, Dec 05 2014
STATUS
approved