A026444 - OEIS

A026444

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

1, 3, 4, 7, 8, 11, 12, 15, 16, 19, 20, 24, 25, 28, 29, 32, 33, 36, 37, 40, 41, 44, 45, 48, 49, 52, 53, 56, 57, 60, 61, 64, 65, 68, 69, 72, 73, 76, 80, 81, 84, 85, 88, 91, 92, 95, 96, 99, 100, 103, 104, 108, 109, 112, 115, 116, 119, 120, 123

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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]]*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: A014601 A154708 A227148 * A003171 A028970 A309388

Adjacent sequences: A026441 A026442 A026443 * A026445 A026446 A026447

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved