OFFSET
1,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (11,-31,21).
FORMULA
Number of m X n binary matrices with no zero rows or columns is Sum_{j=0..m}(-1)^j*C(m, j)*(2^(m-j)-1)^n.
a(n) = 7^n-3*3^n+3.
a(n) = 11*a(n-1)-31*a(n-2)+21*a(n-3). G.f.: -x*(21*x^2+14*x+1) / ((x-1)*(3*x-1)*(7*x-1)). - Colin Barker, Jul 10 2013
MATHEMATICA
LinearRecurrence[{11, -31, 21}, {1, 25, 265}, 30] (* Harvey P. Dale, Aug 15 2014 *)
PROG
(PARI) a(n) = 7^n-3*3^n+3 \\ Charles R Greathouse IV, Feb 10 2017
CROSSREFS
KEYWORD
easy,nonn,nice
AUTHOR
Vladeta Jovovic, Nov 26 2000
EXTENSIONS
More terms from Larry Reeves (larryr(AT)acm.org), Dec 04 2000
More terms from Colin Barker, Jul 10 2013
STATUS
approved