OFFSET
1,1
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..180
FORMULA
a(n) = 6*A142459(2*n, n)/(n+1).
MATHEMATICA
PROG
(Sage)
@CachedFunction
def T(n, k, m):
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 A142459(n, k): return T(n, k, 4)
[A172013(n) for n in (1..30)] # G. C. Greubel, Mar 18 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Roger L. Bagula, Nov 19 2010
EXTENSIONS
Offset and formula corrected by G. C. Greubel, Mar 18 2022
STATUS
approved