A026450 a(n) = least positive integer > a(n-1) and not a(i)*a(j)+2 for i<=1<=j<=n.

2, 3, 4, 5, 7, 9, 13, 15, 19, 21, 24, 25, 26, 31, 33, 34, 35, 36, 39, 42, 43, 45, 46, 48, 49, 53, 55, 56, 57, 58, 60, 61, 63, 66, 69, 71, 73, 75, 76, 79, 81, 82, 84, 85, 87, 89, 90, 91, 96, 99, 103, 105, 109, 111, 113, 115, 117, 120, 121

Offset

1,1

Links

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

Mathematica

a = {2, 3}; 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. A026443 and references therein.

Sequence in context: A117604 A117603 A250553 * A280451 A240178 A039863

Adjacent sequences: A026447 A026448 A026449 * A026451 A026452 A026453

Keyword

nonn

Author

Clark Kimberling

Status

approved