

A059064


Cardmatching numbers (DinnerDiner matching numbers).


0



1, 1, 0, 1, 1, 0, 4, 0, 1, 1, 0, 9, 0, 9, 0, 1, 1, 0, 16, 0, 36, 0, 16, 0, 1, 1, 0, 25, 0, 100, 0, 100, 0, 25, 0, 1, 1, 0, 36, 0, 225, 0, 400, 0, 225, 0, 36, 0, 1, 1, 0, 49, 0, 441, 0, 1225, 0, 1225, 0, 441, 0, 49, 0, 1, 1, 0, 64, 0, 784, 0, 3136, 0, 4900, 0
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OFFSET

0,7


COMMENTS

This is a triangle of card matching numbers. A deck has 2 kinds of cards, n of each kind. The deck is shuffled and dealt in to 2 hands each with n cards. A match occurs for every card in the jth hand of kind j. Triangle T(n,k) is the number of ways of achieving exactly k matches (k=0..2n). An odd number of matches is impossible, so alternating elements in each row of the triangle are zero. The probability of exactly k matches is T(n,k)/((2n)!/n!^2).
Rows have lengths 1,3,5,7,...
Analogous to A008290  Zerinvary Lajos, Jun 22 2005


REFERENCES

F. N. David and D. E. Barton, Combinatorial Chance, Hafner, NY, 1962, Ch. 7 and Ch. 12.
J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, pp. 174178.
R. P. Stanley, Enumerative Combinatorics Volume I, Cambridge University Press, 1997, p. 71.


LINKS

Table of n, a(n) for n=0..73.
F. F. Knudsen and I. Skau, On the Asymptotic Solution of a CardMatching Problem, Mathematics Magazine 69 (1996), 190197.
Barbara H. Margolius, DinnerDiner Matching Probabilities
B. H. Margolius, The DinnerDiner Matching Problem, Mathematics Magazine, 76 (2003), 107118.
S. G. Penrice, Derangements, permanents and Christmas presents, The American Mathematical Monthly 98(1991), 617620.
Index entries for sequences related to card matching


FORMULA

G.f.: sum(coeff(R(x, n, k), x, j)*(t1)^j*(n*kj)!, j=0..n*k) where n is the number of kinds of cards (2 in this case), k is the number of cards of each kind and R(x, n, k) is the rook polynomial given by R(x, n, k)=(k!^2*sum(x^j/((kj)!^2*j!))^n (see Stanley or Riordan). coeff(R(x, n, k), x, j) indicates the of coefficient x^j of the rook polynomial.


EXAMPLE

There are 4 ways of matching exactly 2 cards when there are 2 cards of each kind and 2 kinds of card so T(2,2)=4.


MAPLE

p := (x, k)>k!^2*sum(x^j/((kj)!^2*j!), j=0..k); R := (x, n, k)>p(x, k)^n; f := (t, n, k)>sum(coeff(R(x, n, k), x, j)*(t1)^j*(n*kj)!, j=0..n*k);
for n from 0 to 10 do seq(coeff(f(t, 2, n), t, m)/n!^2, m=0..2*n); od;


MATHEMATICA

p[x_, k_] := k!^2*Sum[x^j/((kj)!^2*j!), {j, 0, k}]; r[x_, n_, k_] := p[x, k]^n; f[t_, n_, k_] := Sum[ Coefficient[r[x, n, k], x, j]*(t1)^j*(n*kj)!, {j, 0, n*k}]; Table[ Table[ Coefficient[f[t, 2, n], t, m]/n!^2, {m, 0, 2n}], {n, 0, 8}] // Flatten (* JeanFrançois Alcover, Jan 25 2013, translated from Maple *)


CROSSREFS

Cf. A008290, A059056A059071.
Cf. A008290.
Sequence in context: A061309 A263655 A329078 * A321316 A185690 A298248
Adjacent sequences: A059061 A059062 A059063 * A059065 A059066 A059067


KEYWORD

nonn,tabf,nice


AUTHOR

Barbara Haas Margolius (margolius(AT)math.csuohio.edu)


STATUS

approved



