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A085895
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Group the natural numbers such that the product of the n-th group is divisible by 2^n. (1), (2), (3,4), (5,6,7,8), (9,10,11,12,13,14),(15,16,17,18), ... Sequence contains the product of the terms of the groups.
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%I #13 Jul 30 2015 07:33:22
%S 1,2,12,1680,2162160,73440,96909120,424097856000,5339572260422400,
%T 57407703889536000,1573144097507348889600,89247024757574635311360000,
%U 131197375012291112448000,6932022668773077815267328000
%N Group the natural numbers such that the product of the n-th group is divisible by 2^n. (1), (2), (3,4), (5,6,7,8), (9,10,11,12,13,14),(15,16,17,18), ... Sequence contains the product of the terms of the groups.
%F From _Chayim Lowen_, Jul 29 2015: (Start)
%F Product_{m=0..n} a(m) = (A085897(n+1)-1)! whence:
%F a(n) = (A085897(n+1)-1)!/a(n-1).
%F a(n) = (A085897(n+1)-1)!/(A085897(n)-1)!. (End)
%e a(3) = 1680 = 5*6*7*8 = 2^3*(5*6*7) is divisible by 2^3=8. (In fact, it is divisible by 2^4, but 5*6*7 is not divisible by 8.)
%Y Cf. A085896, A085897, A085898.
%K nonn
%O 0,2
%A _Amarnath Murthy_ and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jul 10 2003
%E More terms from _Ray Chandler_, Sep 13 2003
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