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A046918 Triangle of coefficients of polynomials p(n), with p(3)=1, p(n) = (1 - t^(2*n - 4))*(1 - t^(2*n - 3))*p(n - 1)/((1 - t^(n - 3))*(1 - t^n)). 1
1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 3, 3, 3, 2, 2, 1, 1, 1, 1, 2, 3, 4, 5, 7, 7, 8, 8, 8, 7, 7, 5, 4, 3, 2, 1, 1, 1, 1, 2, 3, 5, 6, 9, 11, 14, 16, 19, 20, 23, 23, 24, 23, 23, 20, 19, 16, 14, 11, 9, 6, 5, 3, 2, 1, 1, 1, 1, 2, 3, 5, 7, 10, 13, 18, 22, 28, 33, 40, 45, 52, 57, 63, 66, 70, 71 (list; table; graph; refs; listen; history; internal format)
OFFSET

3,9

REFERENCES

J. Riordan, The number of score sequences in tournaments, J. Combin. Theory, 5 (1968), 87-89.

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;

CROSSREFS

Cf. A046919.

Sequence in context: A131619 A048485 A127714 * A060287 A165001 A059253

Adjacent sequences:  A046915 A046916 A046917 * A046919 A046920 A046921

KEYWORD

nonn,easy,nice,tabl

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

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Last modified February 16 21:51 EST 2012. Contains 205978 sequences.