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a(n) = (floor(n/2)+1)^n.
2

%I #10 Oct 08 2016 12:33:00

%S 1,4,8,81,243,4096,16384,390625,1953125,60466176,362797056,

%T 13841287201,96889010407,4398046511104,35184372088832,

%U 1853020188851841,16677181699666569,1000000000000000000,10000000000000000000,672749994932560009201

%N a(n) = (floor(n/2)+1)^n.

%C Functions from [n] to [n] with f(i) even or f(i) = 1 for all i.

%C Functions from [n] to [n] with f(i) odd or f(i) = n for all i.

%t Table[(Floor[n/2] + 1)^n, {n, 1, 20}]

%o (PARI) a(n) = (n\2 + 1)^n; \\ _Michel Marcus_, Oct 08 2016

%Y Cf. A206344, A276978.

%K nonn,easy

%O 1,2

%A _Olivier Gérard_, Sep 23 2016