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a(n) = rad((2n-1)!/(n-1)!).
0

%I #26 May 02 2023 23:53:13

%S 1,6,30,210,210,2310,30030,30030,510510,9699690,9699690,223092870,

%T 223092870,223092870,6469693230,200560490130,200560490130,

%U 200560490130,7420738134810,7420738134810,304250263527210,13082761331670030,13082761331670030,614889782588491410

%N a(n) = rad((2n-1)!/(n-1)!).

%C Squarefree kernel of the product of the larger parts of the partitions of 2n into 2 parts.

%H <a href="/index/Par#part">Index entries for sequences related to partitions</a>

%F a(n) = A007947(A000407(n-1)).

%o (PARI) a(n) = factorback(factorint((2*n-1)!/(n-1)!)[, 1]); \\ _Michel Marcus_, May 01 2023

%Y Cf. A000407, A007947, A034386.

%K nonn

%O 1,2

%A _Wesley Ivan Hurt_, Apr 30 2023