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A026462
a(n) = least positive integer > a(n-1) and not a(i)*a(j)-2 for 1<=i<=j<=n, n >= 2.
2
1, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16, 17, 19, 20, 21, 24, 25, 27, 29, 31, 32, 35, 36, 37, 39, 41, 44, 45, 49, 51, 55, 56, 57, 59, 60, 65, 67, 69, 71, 72, 77, 80, 81, 84, 85, 87, 90, 91, 92, 95, 96, 99, 101, 104, 105, 107, 109, 111
OFFSET
1,2
LINKS
MATHEMATICA
a = {1, 4}; used = {a[[1]]^2 - 2, a[[1]]*a[[2]] - 2, a[[2]]^2 - 2}; Do[k = a[[-1]] + 1; While[MemberQ[used, k], k++]; AppendTo[a, k]; used = Union[used, k*a - 2], {n, 3, 60}]; a (* Ivan Neretin, Mar 06 2016 *)
CROSSREFS
Cf. A026453 and references therein.
Sequence in context: A026440 A299487 A063713 * A039230 A111222 A037357
KEYWORD
nonn
STATUS
approved