A154425 a(n) = A142458(n, 1 + floor(n/2)).

1, 1, 8, 39, 546, 5482, 109640, 1709675, 44451550, 947113254, 30307624128, 821539580358, 31218504053604, 1028949571999572, 45273781167981168, 1758747856988046771, 87937392849402338550, 3935893923685215214030

Offset: 1

Author

Roger L. Bagula, Jan 09 2009

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 1..375

Crossrefs

Cf. A142458.

Programs

Mathematica

T[n_, k_, m_]:= T[n, k, m]= If[k==1 || k==n, 1, (m*n-m*k+1)*T[n-1, k-1, m] + (m*k-m+1)*T[n-1, k, m]];
A154425[n_]:= T[n, 1+Floor[n/2], 3];
Table[A154425[n], {n, 30}] (* modified by G. C. Greubel, Mar 16 2022 *)

Sage

@CachedFunction
def T(n,k,m): # A142458
    if (k==1 or k==n): return 1
    else: return (m*(n-k)+1)*T(n-1,k-1,m) + (m*k-m+1)*T(n-1,k,m)
def A154425(n): return T(n, 1 + (n//2), 3)
[A154425(n) for n in (1..30)] # G. C. Greubel, Mar 16 2022

Formula

a(n) = A142458(n, 1 + floor(n/2)).

Extensions

Edited by G. C. Greubel, Mar 16 2022