OFFSET
0,5
FORMULA
G.f.: Sum_{k>=0} k! * x^k * ( (1-x)/(1-x^6) )^(k+1).
a(n) = Sum_{i, j, k, l, m>=0 and i+2*j+3*k+4*l+5*m<=n} (-1)^(i+j+k+l+m) * (n-j-2*k-3*l-4*m)!/(i!*j!*k!*l!*m!).
PROG
(PARI) my(N=30, x='x+O('x^N)); Vec(sum(k=0, N, k!*x^k*((1-x)/(1-x^6))^(k+1)))
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Feb 22 2024
STATUS
approved