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A084400
a(1) = 1; for n>1, a(n) = smallest number that does not divide the product of all previous terms.
15
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, 71, 73, 79, 81, 83, 89, 97, 101, 103, 107, 109, 113, 121, 127, 131, 137, 139, 149, 151, 157, 163, 167, 169, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239
OFFSET
1,2
COMMENTS
All numbers of the form p^(2^k) are members.
Except for the first term, same as A050376. - David Wasserman, Dec 22 2004
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
LINKS
PROG
(PARI) find(pv)=k = 1; while (! (pv % k), k++); return (k);
lista(nn) = print1(pv=1, ", "); for (i=1, nn, nv = find(pv); pv *= nv; print1(nv, ", ")) \\ Michel Marcus, Aug 12 2015
(PARI) A209229(n)=if(n%2, n==1, isprimepower(n))
is(n)=A209229(isprimepower(n)) || n==1 \\ Charles R Greathouse IV, Oct 19 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, May 31 2003
EXTENSIONS
More terms from Patrick De Geest, Jun 05 2003
STATUS
approved