cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A097399 Maximum of the determinant over all permutations of the entries of a 3 X 3 matrix which are consecutive integers in the range (n-4,n+4).

Original entry on oeis.org

86, 104, 172, 252, 332, 412, 492, 572, 652, 732, 812, 892, 972, 1053, 1134, 1215, 1296, 1377, 1458, 1539, 1620, 1701, 1782, 1863, 1944, 2025, 2106, 2187, 2268, 2349, 2430, 2511, 2592, 2673, 2754, 2835, 2916, 2997, 3078, 3159, 3240, 3321, 3402, 3483, 3564
Offset: 0

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Author

Hugo Pfoertner, Aug 19 2004

Keywords

Examples

			a(0)=86 because the maximal determinant that can achieved using the consecutive integers -4,-3,-2,-1,0,1,2,3,4 as matrix elements of a 3 X 3 matrix is det((-4,-3,0),(1,-1,4),(-2,3,2))=86. Another example for a(5)=412 is given in A085000.
		

Crossrefs

Cf. A097400 = corresponding number of different determinants, A097401, A097693 = maximum of determinant if distinct matrix elements are selected from given range, a(5)=A085000(3) maximal determinant with elements (1..n^2).

Programs

  • Mathematica
    Join[{86,104,172,252,332,412,492,572,652,732,812,892},LinearRecurrence[ {2,-1},{972,1053},40]] (* or *) Table[ Det[ Partition[ #,3]]&/@ Permutations[ Range[n-4,n+4]]//Max,{n,0,45}] (* Harvey P. Dale, Jan 14 2015 *)

Formula

G.f.: (x^13+12*x^3+50*x^2-68*x+86) / (x-1)^2. [Colin Barker, Dec 13 2012] [I suspect this is merely a conjecture. - N. J. A. Sloane, Jun 09 2018]