A094955 Main diagonal of array A094954.

1, 2, 11, 91, 985, 13201, 211303, 3936808, 83739041, 2003229469, 53252096051, 1557702562417, 49731172316281, 1720974414781454, 64174041067789199, 2565470565551429551, 109461497917277584513, 4965206236292285024041

Offset: 1

Author

Ralf Stephan, May 31 2004

Keywords

• nonn

Crossrefs

Cf. A094954.

Programs

Mathematica

Table[DifferenceRoot[Function[{y, m}, {y[1 + m] == n*y[m] - y[m - 1], y[0] == 1, y[1] == 1, y[2] == 1}]][n], {n, 2, 20}] (* Benedict W. J. Irwin, Nov 03 2016 *)

Formula

a(n) = y(n,n), where y(m+1,n)=n*y(m,n)-y(m-1,n), with y(0,n)=y(1,n)=y(2,n)=1 for all n. - Benedict W. J. Irwin, Nov 03 2016

a(n) ~ exp(1) * n^(n-1). - Vaclav Kotesovec, Nov 05 2016