OFFSET
1,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (20,-160,640,-1280,1024).
FORMULA
a(n) = 2^(-5+2*n)*(6+8*n+5*n^2+4*n^3+n^4)/3. - Colin Barker, Oct 24 2014
G.f.: -x*(64*x^4-80*x^3+36*x^2-5*x+1) / (4*x-1)^5. - Colin Barker, Oct 24 2014
MATHEMATICA
LinearRecurrence[{20, -160, 640, -1280, 1024}, {1, 15, 176, 1680, 13824}, 30] (* Harvey P. Dale, Aug 13 2024 *)
PROG
(PARI) for(n=1, 30, print1((-1)^(n+1)*matdet(matrix(n, n, i, j, sum(k=0, n-1, if(abs(i-j)-k, 0, (k+1)^2)))), ", "))
(PARI) Vec(-x*(64*x^4-80*x^3+36*x^2-5*x+1)/(4*x-1)^5 + O(x^100)) \\ Colin Barker, Oct 24 2014
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Jun 20 2002
EXTENSIONS
More terms, and typos in data fixed by Colin Barker, Oct 24 2014
STATUS
approved