A026446 a(n) = least positive integer > a(n-1) and not a(i)*a(j)+2 for 1<=i<j<=n.

2, 4, 5, 6, 7, 8, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 39, 41, 43, 45, 49, 51, 53, 55, 59, 61, 63, 66, 69, 71, 73, 75, 76, 81, 82, 83, 85, 89, 91, 95, 96, 98, 99, 103, 105, 109, 111, 113, 114, 115, 123, 125, 129, 130, 131

Offset

1,1

Links

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

Mathematica

a = {2, 4}; used = {a[[1]]*a[[2]] + 2}; Do[k = a[[-1]] + 1; While[MemberQ[used, k], k++]; used = Union[used, k*a + 2]; AppendTo[a, k], {n, 3, 60}]; a (* Ivan Neretin, Mar 06 2016 *)

Crossrefs

Cf. A026443 and references therein.

Sequence in context: A188372 A345921 A088384 * A167493 A372119 A328107

Adjacent sequences: A026443 A026444 A026445 * A026447 A026448 A026449

Keyword

nonn

Author

Clark Kimberling

Status

approved