This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A080431 #11 Jul 02 2025 16:02:01
%S A080431 2,4,6,8,10,14,18,22,26,32,34,38,46,50,58,60,62,74,82,86,94,98,106,
%T A080431 118,122,134,142,146,158,162,166,168,178,194,202,206,214,218,226,242,
%U A080431 254,256,262,274,278,298,302,308,314,326,334,338,346,358,360,362,382,386
%N A080431 Even numbers such that all a(i)*a(j) are distinct.
%p A080431 S := {8}: A := array(1..10^3): for m from 1 to 10^3 do A[m] := 0 od: A[2] := 2: A[4] := 4: for n from 6 to 10^3 by 2 do mytest := 0: for j from 2 to n-2 by 2 do if A[j]>0 then if member(A[j]*n, S) then mytest := 1; break; fi: fi: od: if mytest=0 then A[n] := n; for j from 2 to n-2 by 2 do S := S union {A[j]*n} od: fi: od: for i from 2 to 10^3 by 2 do if A[i]>0 then printf(`%d,`, A[i]) fi: od: # _James Sellers_, Feb 26 2003
%Y A080431 Cf. A080430, A080432.
%Y A080431 Equals 2*A066724.
%K A080431 nonn
%O A080431 1,1
%A A080431 _Amarnath Murthy_, Feb 20 2003
%E A080431 More terms from _James Sellers_, Feb 26 2003