2078328

Appears in sequences

• If f[x]=(sum of unitary-proper divisors of x)=A063919[x] is iterated, the iteration may lead to a fixed point which is either 0 or belongs to A002827, a unitary-perfect-number >1: 6,60,90,87360... Sequence gives initial values for which the iteration ends in 87360, the 4th unitary perfect number.at n=21A098186
• Number of compositions (ordered partitions) of n into distinct parts not greater than n/2.at n=44A368501