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A071535 (-1)^(n+1) * Determinant of n X n matrix of form [1^2 2^2 3^2 4^2 5^2 / 2^2 1^2 2^2 3^2 4^2 / 3^2 2^2 1^2 2^2 3^2 / 4^2 3^2 2^2 1^2 2^2 / 5^2 4^2 3^2 2^2 1^2]. 0
1, 15, 176, 1680, 13824, 102144, 696320, 4460544, 27197440, 159318016, 902823936, 4975493120, 26776436736, 141180272640, 731218182144, 3728300048384, 18747532247040, 93110596009984, 457328117678080, 2223830986653696, 10715840324304896, 51209754063667200 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..22.

Index to sequences with 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

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

Sequence in context: A120995 A024197 A210782 * A081043 A155000 A009146

Adjacent sequences:  A071532 A071533 A071534 * A071536 A071537 A071538

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

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Last modified December 22 00:23 EST 2014. Contains 252326 sequences.