A026451 a(n) = least positive integer > a(n-1) and not a(i)*a(j)+2 for i<=1<=j<=n, n >= 2.

2, 4, 5, 7, 8, 9, 11, 13, 14, 15, 17, 19, 21, 23, 25, 26, 29, 31, 33, 35, 39, 41, 43, 45, 49, 50, 53, 55, 56, 59, 61, 63, 69, 71, 73, 75, 76, 81, 82, 85, 89, 91, 95, 96, 98, 99, 103, 104, 105, 109, 110, 111, 113, 115, 116, 125, 129, 130

Offset

1,1

Links

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

Mathematica

a = {2, 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. A026443 and references therein.

Sequence in context: A039046 A187683 A187351 * A050106 A345917 A303739

Adjacent sequences: A026448 A026449 A026450 * A026452 A026453 A026454

Keyword

nonn

Author

Clark Kimberling

Status

approved