A378118 - OEIS

%I #4 Nov 17 2024 07:13:48

%S 1,1,2,12,21840,

%T 2814355154336774377799951925175856161820370339122436787831200

%N a(n) is the multinomial coefficient given by the previous terms, i.e., a(n) = (a(1)+...+a(n-1))!/(a(1)!*...*a(n-1)!).

%C a(7) = 6153915608...9019200000 (1235886 digits).

%e a(1) = 1 (0! divided by the empty product).

%e a(2) = 1!/1! = 1.

%e a(3) = (1+1)!/(1!*1!) = 2.

%e a(4) = (1+1+2)!/(1!*1!*2!) = 12.

%e a(5) = (1+1+2+12)!/(1!*1!*2!*12!) = 21840.

%K nonn,new

%O 1,3

%A _Pontus von Brömssen_, Nov 17 2024