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A232553 Maximal values of permanent on (0,1) square matrices of order n with row and column sums 3. 2
6, 9, 13, 36, 54, 81, 216, 324, 486, 1296, 1944, 2916, 7776, 11664, 17496, 46656, 69984, 104976, 279936, 419904, 629856, 1679616, 2519424, 3779136, 10077696, 15116544, 22674816, 60466176, 90699264, 136048896, 362797056, 544195584, 816293376, 2176782336, 3265173504, 4897760256 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,1

COMMENTS

a(n) attains on subset of symmetric matrices with the main diagonal of 1's.

LINKS

Colin Barker, Table of n, a(n) for n = 3..1000

D. Merriell, The maximum permanents in Lambda_n,k, Linear and Multilinear Algebra, 1980, no.9, 81-91.

V. S. Shevelev, Some problems of the theory of enumerating the permutations with restricted position, Journal of Soviet Mathematics, 61 (4) (1992) 2272-2317

Index entries for linear recurrences with constant coefficients, signature (0,0,6).

FORMULA

a(n) = floor(6^((n-h)/3)*(3/2)^h), where h=0,1 or 2, such that n == h (mod 3).

From Colin Barker, May 27 2016: (Start)

a(n) = 6*a(n-3) for n>5.

G.f.: x^3*(6+9*x+13*x^2+3*x^5) / (1-6*x^3).

(End)

PROG

(PARI) a(n) = h = n%3; floor(6^((n-h)/3)*(3/2)^h); \\ Michel Marcus, Nov 26 2013

(PARI) Vec(x^3*(6+9*x+13*x^2+3*x^5)/(1-6*x^3) + O(x^50)) \\ Colin Barker, May 27 2016

CROSSREFS

Cf. A176211, A176212, A185177, A185178, A185179.

Sequence in context: A315974 A176211 A176212 * A155705 A267369 A177891

Adjacent sequences:  A232550 A232551 A232552 * A232554 A232555 A232556

KEYWORD

nonn,easy

AUTHOR

Vladimir Shevelev, Nov 26 2013

STATUS

approved

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Last modified October 15 12:00 EDT 2018. Contains 316232 sequences. (Running on oeis4.)