669900

Appears in sequences

• Smaller of unitary amicable pair.at n=15A002952
• Unitary amicable numbers.at n=30A063991
• Numbers k such that sopfr(k) = ud(k), where sopfr = A001414 and ud = A034444.at n=16A064029
• Lesser of modified exponential amicable pairs.at n=28A323758
• Lesser of tri-unitary amicable numbers pair: numbers (m, n) such that tsigma(m) = tsigma(n) = m + n, where tsigma(n) is the sum of the tri-unitary divisors of n (A324706).at n=34A324708
• a(n) is the smallest member of the n-th purely periodic unitary sigma aliquot cycle listed in A336216.at n=27A336219