%I A076221
%S A076221 0,1,1,2,2,2,3,2,3,2,4,3,4,3,4,5,3,4,3,5,2,6,4,5,4,6,3,6,7,4,6,4,7,3,7,
%T A076221 4,8,5,6,5,8,3,8,5,6,9,5,7,5,8,3,9,5,7,4,10,6,8,6,9,4,10,6,8,5,10,11,6,
%U A076221 8,6,10,4,11,6,8,5,11,4,12,7,9,7,11,5,12,7,9,6,12,5,12,13,7,10,7,12,5
%N A076221 Table of number of pairs (a,b) of relatively prime numbers <= n containing 
               i.
%C A076221 Last entry of each row is Euler totient function phi(n).
%C A076221 {{0}, {1, 1}, {2, 2, 2}, {3, 2, 3, 2}, {4, 3, 4, 3, 4}, {5, 3, 4, 3, 
               5, 2}}
%e A076221 a(22)=A(5,6) is 5 because (1,5), (2,5), (3,5), (4,5) and (5,6) are the 
               five pairs of relatively primes integers <= 6.
%Y A076221 Sequence in context: A164024 A145193 A143117 this_sequence A029235 A106696 
               A131839
%Y A076221 Adjacent sequences: A076218 A076219 A076220 this_sequence A076222 A076223 
               A076224
%K A076221 nonn,tabl
%O A076221 1,4
%A A076221 Olivier Gerard (olivier.gerard(AT)gmail.com)