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%I #8 Apr 12 2018 08:43:28
%S 3,2,12,24,48,60,192,168,180,240,5120,360,20480,2112,720,840,983040,
%T 1260,786432,3024,2880,15360,62914560,3360,22032,266240,6300,6720,
%U 13690208256,5040,22548578304,7560,156672,6881280,25920,10080
%N a(n) = smallest k such that tau(k)= n*tau(k-1) where tau(k) = number of divisors of k, or 0 if no such number exists.
%C Conjectures: (1) No term is zero. (2) a(n)-1 is a prime.
%C 17 is the first n such that a(n)-1 is composite. a(17) = 2^16*3*5 and a(17)-1 is a product of two primes. - _David Wasserman_, Mar 24 2005
%e a(6) = 60 as tau(60)/ tau(59) = 12/2 = 6.
%Y Cf. A086550.
%K nonn
%O 1,1
%A _Amarnath Murthy_, Aug 28 2003
%E More terms from _David Wasserman_, Mar 24 2005