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.

A090015 Permanent of (0,1)-matrix of size n X (n+d) with d=5 and n-1 zeros not on a line.

Original entry on oeis.org

6, 36, 258, 2136, 19998, 208524, 2393754, 29976192, 406446774, 5930064372, 92608986546, 1541044428456, 27216454135758, 508388707585116, 10013199347882058, 207381428863832784, 4505207996358719334
Offset: 1

Views

Author

Jaap Spies, Dec 13 2003

Keywords

References

  • Brualdi, Richard A. and Ryser, Herbert J., Combinatorial Matrix Theory, Cambridge NY (1991), Chapter 7.

Crossrefs

Programs

  • Maple
    f:= gfun:-rectoproc({a(n) = (n+4)*a(n-1) + (n-2)*a(n-2),a(1)=6,a(2)=36},a(n),remember):
    map(f, [$1..40]); # Robert Israel, Nov 26 2018
  • Mathematica
    t={6,36};Do[AppendTo[t,(n+4)*t[[-1]]+(n-2)*t[[-2]]],{n,3,17}];t (* Indranil Ghosh, Feb 21 2017 *)
    RecurrenceTable[{a[n] == (n+4)*a[n-1] + (n-2)*a[n-2],
    a[1] == 6, a[2] == 36}, a, {n, 1, 40}] (* Jean-François Alcover, Sep 16 2022, after Robert Israel *)

Formula

a(n) = (n+4)*a(n-1) + (n-2)*a(n-2), a(1)=6, a(2)=36
a(n) ~ exp(-1) * n! * n^5 / 5!. - Vaclav Kotesovec, Nov 30 2017
a(n) = ((n^6+21*n^5+160*n^4+545*n^3+814*n^2+415*n+1)*exp(-1)*Gamma(n, -1)+(-1)^n*(n^5+20*n^4+141*n^3+422*n^2+499*n+154))/120. - Robert Israel, Nov 26 2018

Extensions

Corrected by Jaap Spies, Jan 26 2004