%I #11 Oct 13 2012 15:19:43
%S 1,14,7,2,54,91,323,141,44360,48919,218972,534078,2699915,526095,
%T 17233173,127890362,29138958036,146216247221,118968284928
%N Let d(n) = number of distinct primes dividing n (A001221). Find smallest t such that d(t)=d(t+1)=...=d(t+n-1) but d(t-1) and d(t+n) are not = d(t); then a(n)=t.
%C a(n) > 10^13 for n from 20 to 22. a(23) = 585927201062. [From _Donovan Johnson_, Jul 30 2010]
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/CubicNumber.html">Cubic number.</a>
%e a(3)=7 since 7,8,9 all have d = 1 but d(6) and d(10) != 1 and this is the first run of 3.
%Y First occurrence of a run of length exactly n in A001221. Cf. A048971, A048972.
%K easy,nonn
%O 1,2
%A _Enoch Haga_
%E More terms from _Naohiro Nomoto_, Jul 13 2001
%E a(16)-a(19) from _Donovan Johnson_, Jul 30 2010