83021

Appears in sequences

• G.f.: A(x) = exp( Sum_{n>=1} A(2^(n^2)*x^n)*x^n/n ).at n=6A181535
• Numbers n such that phi(n) = 3*phi(n+1).at n=14A256907
• a(n) is the smallest positive integer which can be represented as the sum of n distinct nonzero square pyramidal numbers in exactly n ways, or -1 if no such integer exists.at n=27A360218