The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A204265 Permanent of n X n matrix M with M(i,j) = (i+j) (mod 3). 2
 2, 2, 9, 40, 144, 1032, 7824, 48816, 530712, 5619456, 50015232, 707802624, 9591229440, 112586112000, 1938416832000, 32061464064000, 469224244224000, 9509523337728000, 185772505605120000, 3261008730405888000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Permanent of the n-th principal submatrix of A204263. LINKS MATHEMATICA f[i_, j_] := Mod[i + j, 3]; m[n_] := Table[f[i, j], {i, 1, n}, {j, 1, n}] TableForm[m[8]] (* 8x8 principal submatrix *) Flatten[Table[f[i, n + 1 - i],   {n, 1, 14}, {i, 1, n}]]    (* A204263 *) Permanent[m_] :=   With[{a = Array[x, Length[m]]},    Coefficient[Times @@ (m.a), Times @@ a]]; Table[Permanent[m[n]], {n, 1, 22}]    (* A204265 *) PROG (PARI) matperm(M)=my(n=#M, t); sum(i=1, n!, t=numtoperm(n, i); prod(j=1, n, M[j, t[j]])); a(n)=matperm(matrix(n, n, i, j, (i+j)%3)) \\ Ralf Stephan, Oct 19 2013 CROSSREFS Cf. A204263. Sequence in context: A220971 A308519 A205390 * A081086 A019514 A135816 Adjacent sequences:  A204262 A204263 A204264 * A204266 A204267 A204268 KEYWORD nonn AUTHOR Clark Kimberling, Jan 15 2012 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified January 18 12:44 EST 2021. Contains 340254 sequences. (Running on oeis4.)