OFFSET
1,3
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..375
FORMULA
a(n) = A142458(n, 1 + floor(n/2)).
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 *)
PROG
(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
CROSSREFS
KEYWORD
nonn
AUTHOR
Roger L. Bagula, Jan 09 2009
EXTENSIONS
Edited by G. C. Greubel, Mar 16 2022
STATUS
approved