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%I #9 Aug 06 2017 22:31:00
%S 1,4,126,12870,3268760,3796297200,3348108992991,19619725782651120,
%T 95399637739311016800,1917353200780443050763600,
%U 7359958875023243471254188840,3720132147124647210937719983999040
%N a(n) = binomial(A000290(n), A006218(n)).
%C This sequence counts combinations that are possible to create by moving around the numbers in A051731. It would be interesting to know what values the determinant can take for such combinations.
%p A000290 := proc(n) n^2 ; end: A006218 := proc(n) local k ; add( floor(n/k),k=1..n) ; end: A152421 := proc(n) binomial(A000290(n),A006218(n)) ; end: for n from 1 to 30 do printf("%d,",A152421(n)) ; od: # _R. J. Mathar_, Jan 22 2009
%K nonn
%O 1,2
%A _Mats Granvik_, Dec 03 2008
%E Terms beyond a(5) from _R. J. Mathar_, Jan 22 2009
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