71440

Appears in sequences

• a(n) is the square of the n-th partial sum minus the n-th partial sum of the squares, divided by a(n-1), for all n>=1, starting with a(0)=1, a(1)=2.at n=15A087955
• Sum of the parts in the partitions of 4n into 4 parts with smallest part equal to 1 minus the number of these partitions.at n=23A239057
• a(n) = Sum_{i=1..n} 2^phi(i), where phi=A000010.at n=16A385147