The row sum of Φ n {\displaystyle \Phi _{n}} for n ≥ 1 {\displaystyle n\geq 1} is 2 a ⋅ ( 2 b − 1 ) = 2 a + b − 2 a {\displaystyle ~~~2^{a}\cdot (2^{b}-1)~~~=~~~2^{a+b}-2^{a}~~~} with a = 2 n − 1 {\displaystyle ~~~a=2^{n-1}~~~} and b = 2 n − 1 {\displaystyle ~~~b=2^{n}-1~~~} . That is a binary number consisting of a {\displaystyle a} 0s at the little and b {\displaystyle b} 1s at the big end.
E.g. that of Φ 2 {\displaystyle \Phi _{2}} is 0 + 6 + 8 + 14 = 28. (11100 as a binary number.)
for 
is 
with 
and 
.
0s at the little and 
1s at the big end.
is 0 + 6 + 8 + 14 = 28. (11100 as a binary number.)
