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%I #18 Oct 19 2015 11:57:20
%S 1,2,3,4,5,7,9,11,13,16,17,19,23,25,29,31,37,41,43,47,49,53,59,61,67,
%T 71,73,79,81,83,89,97,101,103,107,109,113,121,127,131,137,139,149,151,
%U 157,163,167,169,173,179,181,191,193,197,199,211,223,227,229,233,239
%N a(1) = 1; for n>1, a(n) = smallest number that does not divide the product of all previous terms.
%C All numbers of the form p^(2^k) are members.
%C Except for the first term, same as A050376. - _David Wasserman_, Dec 22 2004
%C Also, the lexicographically earliest sequence of distinct positive integers such that the number of divisors of the product of n initial terms (for any n) is a power of 2. - _Ivan Neretin_, Aug 12 2015
%H Giovanni Resta, <a href="/A084400/b084400.txt">Table of n, a(n) for n = 1..10000</a>
%o (PARI) find(pv)=k = 1; while (! (pv % k), k++); return (k);
%o lista(nn) = print1(pv=1, ", "); for (i=1, nn, nv = find(pv); pv *= nv; print1(nv, ", ")) \\ _Michel Marcus_, Aug 12 2015
%o (PARI) A209229(n)=if(n%2, n==1, isprimepower(n))
%o is(n)=A209229(isprimepower(n)) || n==1 \\ _Charles R Greathouse IV_, Oct 19 2015
%Y Cf. A000040 (primes), A026416, A000028, A066724, A026477, A050376.
%K nonn
%O 1,2
%A _Amarnath Murthy_, May 31 2003
%E More terms from _Patrick De Geest_, Jun 05 2003
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