A026443 - OEIS

%I #11 Mar 06 2016 03:48:50

%S 1,2,3,6,7,10,11,15,18,19,25,26,29,30,33,34,37,41,42,45,46,49,50,53,

%T 57,58,61,64,65,69,73,74,78,81,82,85,88,91,95,96,99,103,106,109,114,

%U 115,119,120,123,126,127,131,134,138,139,142,143

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

%H Ivan Neretin, <a href="/A026443/b026443.txt">Table of n, a(n) for n = 1..1000</a>

%t a = {1, 2}; used = {a[[1]]*a[[2]] + 2}; Do[k = a[[-1]] + 1;

%t  While[MemberQ[used, k], k++]; used = Union[used, k*a + 2];

%t AppendTo[a, k], {n, 3, 60}]; a (* _Ivan Neretin_, Mar 06 2016 *)

%Y Similar sequences with different starting conditions: A026444 (1,3), A026445 (2,3), A026446 (2,4), A026447 (3,4).

%Y Related sequences with definition using any products (not necessarily distinct) and with various starting conditions: A026448 (1,2), A026449 (1,3), A026450 (2,3), A026451 (2,4), A026452 (3,4).

%K nonn

%O 1,2

%A _Clark Kimberling_