A026435 a(n) = least positive integer > a(n-1) and not a(i)*a(j)-1 for 1<=i<j<=n.

2, 4, 5, 6, 8, 10, 12, 13, 14, 16, 17, 18, 20, 21, 22, 24, 26, 28, 30, 32, 34, 36, 37, 38, 40, 42, 44, 45, 46, 48, 50, 52, 53, 54, 56, 57, 58, 60, 61, 62, 65, 66, 68, 70, 72, 74, 76, 78, 80, 81, 82, 85, 86, 88, 90, 92, 93, 94, 96, 97

Offset

1,1

Links

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

Mathematica

a = {2, 4}; used = {a[[1]]*a[[2]] - 1}; Do[k = a[[-1]] + 1; While[MemberQ[used, k], k++]; used = Union[used, k*a - 1]; AppendTo[a, k], {n, 3, 60}]; a (* Ivan Neretin, Mar 07 2016 *)

Crossrefs

Cf. A026431 and references therein.

Sequence in context: A337140 A171946 A285385 * A026437 A026441 A047434

Adjacent sequences: A026432 A026433 A026434 * A026436 A026437 A026438

Keyword

nonn

Author

Clark Kimberling

Status

approved