A108207 a(n)= 5*(n-1)*a(n-1) -(n-1)*a(n-2), with a(0)=0, a(1)=1.

0, 1, 5, 48, 705, 13908, 344175, 10241802, 356053845, 14160219384, 634005387675, 31558667189910, 1728752636180625, 103346454164558580, 6695045736425959575, 467206351191513350130, 34940050653317111866125

Offset

0,3

Comments

This is also the (2,2) element of the product matrix after multiplying the unit matrix from the

left by the matrices (0,-1;j-1,5j-5) in the order j=2 to n.

Links

Table of n, a(n) for n=0..16.

Mathematica

M[n_] := {{0, -1}, {(n - 1), 5*(n - 1)}} v[1] = {0, 1} v[n_] := v[n] = M[n].v[n - 1] a = Table[Abs[v[n][[1]]], {n, 1, 25}]
RecurrenceTable[{a[0]==0, a[1]==1, a[n]==5(n-1)a[n-1]-(n-1)a[n-2]}, a[n], {n, 20}] (* Harvey P. Dale, Aug 19 2011 *)

Crossrefs

Cf. A000166.

Sequence in context: A023999 A126224 A360235 * A127091 A370758 A352254

Adjacent sequences: A108204 A108205 A108206 * A108208 A108209 A108210

Keyword

nonn,easy

Author

Roger L. Bagula, Jun 15 2005

Extensions

Definition replaced by recurrence by the Associate Editors of the OEIS, Sep 28 2009

Status

approved