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a(n) = product of numbers from 1 to sigma(n), where sigma(n) = A000203(n).
8

%I #8 Apr 09 2019 15:44:43

%S 1,6,24,5040,720,479001600,40320,1307674368000,6227020800,

%T 6402373705728000,479001600,304888344611713860501504000000,

%U 87178291200,620448401733239439360000,620448401733239439360000,8222838654177922817725562880000000,6402373705728000

%N a(n) = product of numbers from 1 to sigma(n), where sigma(n) = A000203(n).

%F a(n) = sigma(n)! = Product_(i = 1,…,sigma(n)) i = A000142(A000203(n)) = (A000203(n))!.

%e For n = 4; sigma(4) = 7; a(n) = 1*2*3*4*5*6*7 = 5040.

%t DivisorSigma[1,Range[20]]! (* _Harvey P. Dale_, Apr 09 2019 *)

%o (PARI) a(n)=sigma(n)! \\ _Charles R Greathouse IV_, Feb 13 2013

%Y Cf. A184387, A184389, A184390, A184391, A130674.

%K nonn

%O 1,2

%A _Jaroslav Krizek_, Jan 12 2011

%E Corrected and extended by _Harvey P. Dale_, Apr 09 2019