OFFSET
2,2
REFERENCES
J. A. Hendrickson, Jr., Submatrices of 0,1 matrices, Problem 1470, Math. Mag., 69 (No. 2, 1996), 146-148.
LINKS
Colin Barker, Table of n, a(n) for n = 2..1000
Index entries for linear recurrences with constant coefficients, signature (2,0,-2,1).
FORMULA
G.f.: x^3*(-3-10*x+5*x^2) / ( (1+x)*(x-1)^3 ). - R. J. Mathar, Jun 18 2015
a(n) = -a(n-1)-12*n+3+4*n^2, n>=3. - R. J. Mathar, Nov 07 2015
a(n) = 2*a(n-1)-2*a(n-3)+a(n-4) for n>5.
MAPLE
f:=n-> if (n mod 2)=0 then 2*n^2-4*n else 2*n^2-4*n-3; fi;
PROG
(PARI) concat(0, Vec(x^3*(5*x^2-10*x-3)/((x-1)^3*(x+1)) + O(x^50))) \\ Colin Barker, Apr 02 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Jun 16 2015
EXTENSIONS
Crossref corrected by Colin Barker, Apr 02 2016
STATUS
approved