A026449 - OEIS

A026449

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

1, 3, 4, 7, 8, 12, 13, 16, 17, 20, 21, 24, 25, 28, 29, 32, 33, 36, 37, 40, 43, 44, 47, 48, 52, 55, 56, 59, 60, 63, 64, 67, 68, 71, 72, 75, 76, 79, 80, 83, 84, 87, 88, 91, 92, 95, 96, 99, 100, 103, 104, 107, 108, 111, 112, 115, 116, 119, 120

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OFFSET

1,2

LINKS

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

MATHEMATICA

a = {1, 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: A045615 A211220 A051201 * A286904 A282166 A165157

Adjacent sequences: A026446 A026447 A026448 * A026450 A026451 A026452

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved