OFFSET
1,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..310
FORMULA
a(n) = Sum_{k=1..n} Bo(n-k+1, k), where Bo(r, n) = A094416(r, n).
MATHEMATICA
Table[Sum[Sum[j!*(n - k + 1)^j*StirlingS2[k, j], {j, 0, n}], {k, 1, n}], {n, 1, 20}] (* Vaclav Kotesovec, Jul 23 2018 *)
PROG
(Magma)
A094422:= func< n | (&+[(&+[Factorial(j)*(n-k+1)^j*StirlingSecond(k, j): j in [0..n]]): k in [1..n]]) >;
[A094422(n): n in [1..25]]; // G. C. Greubel, Jan 11 2024
(SageMath)
def f(n, k, j): return factorial(j)*(n-k+1)^j*stirling_number2(k, j)
def A094422(n): return sum(sum(f(n, k, j) for j in range(n+1)) for k in range(1, n+1))
[A094422(n) for n in range(1, 26)] # G. C. Greubel, Jan 11 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Ralf Stephan, May 02 2004
STATUS
approved