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a(n) = sigma(n!!) where n!! is A006882(n).
3

%I #16 Jun 12 2016 02:48:25

%S 1,1,3,4,15,24,124,192,1020,1920,12264,23040,159666,322560,2555280,

%T 5041344,40893840,90744192,761260368,1814883840,15732804296,

%U 38900010240,377587663200,933600245760,9087075973248,23520702965760,254438142416640

%N a(n) = sigma(n!!) where n!! is A006882(n).

%H G. C. Greubel, <a href="/A167367/b167367.txt">Table of n, a(n) for n = 0..500</a>

%F a(n) = A000203(A006882(n)). - _R. J. Mathar_, Feb 07 2011

%t Join[{1},Array[DivisorSigma[1,#!! ]&,50,1]]

%o (PARI) a(n)=sigma(prod(i=0, (n-1)\2, n - 2*i )) \\ _Charles R Greathouse IV_, May 01 2016

%Y Cf. A062569.

%K nonn

%O 0,3

%A _Vladimir Joseph Stephan Orlovsky_, Nov 01 2009