A114358 - OEIS

A114358

Let M(n) be the n X n matrix m(i,j)=min(i,j) for 1<=i,j<=n then a(n) is the trace of M(n)^(-6).

1, 322, 1186, 2110, 3034, 3958, 4882, 5806, 6730, 7654, 8578, 9502, 10426, 11350, 12274, 13198, 14122, 15046, 15970, 16894, 17818, 18742, 19666, 20590, 21514, 22438, 23362, 24286, 25210, 26134, 27058, 27982, 28906, 29830, 30754, 31678

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OFFSET

1,2

COMMENTS

More generally for any n>=floor((m+1)/2) the trace of M(n)^(-m) = binomial(2*m,m)*n-2^(2*m-1)+binomial(2*m-1,m).

LINKS

Table of n, a(n) for n=1..36.

Index entries for linear recurrences with constant coefficients, signature (2,-1).

FORMULA

a(n) = 924n-1586 with n>2, a(1)=1, a(2)=322.

a(n) = 2*a(n-1)-a(n-2) for n>4. G.f.: x*(1+320*x+543*x^2+60*x^3)/(1-x)^2. [Colin Barker, Mar 18 2012]

CROSSREFS

Cf. A114359, A114360, A114361.

Sequence in context: A004967 A251231 A252274 * A158305 A237406 A234712

Adjacent sequences: A114355 A114356 A114357 * A114359 A114360 A114361

KEYWORD

nonn,easy

AUTHOR

Benoit Cloitre, Feb 09 2006

STATUS

approved