A026423 a(n) = least positive integer > a(n-1) and not a(i)*a(j) for 1<=i<=j<=n, n >= 2.

1, 3, 4, 5, 6, 7, 8, 10, 11, 13, 14, 17, 19, 22, 23, 26, 27, 29, 31, 34, 37, 38, 41, 43, 45, 46, 47, 53, 54, 58, 59, 61, 62, 63, 67, 71, 72, 73, 74, 75, 79, 82, 83, 86, 89, 90, 94, 96, 97, 99, 101, 103, 105, 106, 107, 109, 113, 117, 118, 120

Offset

1,2

Links

Ivan Neretin, Table of n, a(n) for n = 1..1000

Mathematica

a = {1, 3}; used = {a[[1]]^2, a[[1]]*a[[2]], a[[2]]^2}; Do[k = a[[-1]] + 1; While[MemberQ[used, k], k++]; AppendTo[a, k]; used = Union[used, k*a], {n, 3, 60}]; a (* Ivan Neretin, Mar 07 2016 *)

Crossrefs

Cf. A026416 and references therein.

Sequence in context: A298003 A207966 A097901 * A026427 A026482 A232803

Adjacent sequences: A026420 A026421 A026422 * A026424 A026425 A026426

Keyword

nonn

Author

Clark Kimberling

Status

approved