A062155 Number of n-row matrices over {0,1,2} with all row and column sums equal to 1 or 2.

1, 3, 38, 1107, 58938, 5002470, 620355870, 105848185590, 23785613520480, 6809213491925040, 2419333087316808600, 1044664066287091958400, 538796052743780959419600, 327150260492074733413299600, 230994366606893955257329737600, 187668642106165851767306588418000

Offset: 0

Author

Vladeta Jovovic, Jun 06 2001

Keywords

• easy
• nonn

Examples

			There are 38 2-row matrices over {0,1,2} with all row and column sums equal to 1 or 2: 1 of type 2 X 1, 13 of type 2 X 2, 18 of type 2 X 3 and 6 of type 2 X 4, cf. A062154.
		

References

• I. P. Goulden and D. M. Jackson, Combinatorial Enumeration, Wiley, N.Y., 1983,(Problem 3.4.15).

Links

• Andrew Howroyd, Table of n, a(n) for n = 0..100

Crossrefs

Row sums of A062154.

Cf. A062156.

Programs

PARI

seq(n)={[subst(serlaplace(p),y,1) | p <- Vec(serlaplace(1/sqrt(1-x*y + O(x*x^n))*exp(x*y/2+1/(1-x*y)*(x*y+x^2*y/2+x*y^2/2) + O(x*x^n))))]} \\ Andrew Howroyd, Feb 03 2021

Extensions

Terms a(14) and beyond from Andrew Howroyd, Feb 03 2021