A007876 - OEIS

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A007876

a(2n-1) = n*a(2n-2), a(2n) = n*a(2n-1) + 1.

%I #2 May 16 2003 03:00:00

%S 1,2,4,9,27,82,328,1313,6565,32826,196956,1181737,8272159,57905114,

%T 463240912,3705927297,33353345673,300180111058,3001801110580,

%U 30018011105801,330198122163811,3632179343801922,43586152125623064

%N a(2n-1) = n*a(2n-2), a(2n) = n*a(2n-1) + 1.

%K nonn,easy

%O 1,2

%A buzzard(AT)math.berkeley.edu (Kevin Buzzard)