0,3

Let f(x) be a monic polynomial of degree n. Let u be any number and let m be the matrix of values f(u+i-j) for i,j=1..n. Then the determinant of m is a(n). [From T. D. Noe (noe(AT)sspectra.com), Aug 23 2008]

Comments from Andrew Weimholt (andrew(AT)weimholt.com), Sep 23 2009 (Start): Also, number of ways to assemble an n-simplex from n+1 labeled (n-1)-simplices with labeled vertices, where left-handed and right-handed counterparts are considered equivalent.

For n=2, we are constructing a triangle from 3 labeled line-segments with labeled endpoints. Solutions which differ by a rotation or a reflection are considered equivalent. Because reflections are equivalent, there is only 1 way to order the line-segments, and each line-segment can be oriented in 2 ways, so the total number of solutions is 2^3 = 8. For n=3, we are constructing a tetrahedron from 4 labeled triangles with labeled vertices. Without loss of generality, we can pick one labeled triangle to serve as our face of reference. For this face, we do not care which side of the triangle will face the interior

of the tetrahedron as this just translates into a reflection of the tetrahedron, nor do we care about which rotation we pick as these just translate into rotations of the tetrahedron. From this reference triangle, there are 6 (=3!) ways to assign the remaining triangles to the faces of the tetrahedron, and each triangle can be oriented in 6 (=3!) ways (we can pick which side of the triangle will face the interior of the tetrahedron, and we can pick from 3 rotations). This gives 6^4 solutions.

Cf. A165644 (same idea, but reflections are distinct). A165642 and A165643 are the corresponding sequences for cubes instead of simplices. (End)

E. W. Weisstein, MathWorld: Fibonacci Polynomial [From T. D. Noe (noe(AT)sspectra.com), Aug 22 2008]

a(n) = (n!)^(n+1) = a(n-1) * n^n * n!

a(n)=A000178(n)*A002109(n) i.e. product of superfactorials and hyperfactorials [From Henry Bottomley (se16(AT)btinternet.com), Nov 13 2009]

(n!)^(n+1);

a[0]:=1:for n from 1 to 20 do a[n]:=product(n!, k=0..n) od: seq(a[n], n=0..8); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 11 2007

seq(mul(mul(j, j=1..n), k=0..n), n=0..8); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Sep 21 2007

Cf. A036740.

Sequence in context: A027668 A162139 A095821 this_sequence A162090 A017187 A001418

Adjacent sequences: A091865 A091866 A091867 this_sequence A091869 A091870 A091871

easy,nonn,nice,new

Nicolau C. Saldanha (nicolau(AT)mat.puc-rio.br), Mar 10 2004

Edited by N. J. A. Sloane, Oct 24 2009 at the suggestion of R. J. Mathar