A162520 - OEIS

%I #5 Mar 08 2013 16:47:16

%S 1,1,1,2,1,3,1,4,1,5,1,6,1,7,1,8,1,9,2,1,2,2,2,3,2,4,2,5,2,6,2,7,2,8,

%T 2,9,3,1,3,2,3,3,3,4,3,5,3,6,3,7,3,8,3,9,4,1,4,2,4,3,4,4,4,5,4,6,4,7,

%U 4,8,4,9,5,1,5,2,5,3,5,4,5,5,5,6,5,7,5,8,5,9,6,1,6,2,6,3,6,4,6,5,6,6

%N Pairs (i,j) of positive integers where j<10.

%C Note that first 144 pairs, (1,1) to (16,9), are related to the influenza A virus which causes influenza in birds and some mammals. The influenza A virus has 144 subtypes: H1N1, H1N2, H1N3, H1N4, H1N5, H1N6, H1N7, H1N8, H1N9, H2N1, H2N2, ..., H16N8 and H16N9.

%K easy,nonn

%O 1,4

%A _Omar E. Pol_, Jul 06 2009