28828800

Appears in sequences

• a(n) is the smallest number x such that floor(sigma(sigma(x))/x) = n or the A098219(x) quotient equals n.at n=21A098221
• a(2) = 1 by definition; otherwise a(n) = A109347(n)/n.at n=8A110348
• Magic products of 6 X 6 multiplicative magic squares.at n=2A113026
• Triangle read by rows: Joffe's central differences of zero, T(n,k), 1 <= k <= n.at n=24A241171
• Number of permutations of [2n+1] beginning with exactly n ascents.at n=7A262035
• a(n) is the least integer k such that sigma(sigma(k)) >= n*k where sigma is A000203, the sum of divisors.at n=21A327630
• Zeckendorf-infinitary perfect numbers: numbers k such that A331107(k) = 2*k.at n=7A331108
• Dual-Zeckendorf-infinitary perfect numbers: numbers k such that A331110(k) = 2*k.at n=4A331111
• Squares of terms are the intersection of A025487 and A217584.at n=10A333969
• Refactorable numbers (A033950) having more divisors than all smaller refactorable numbers.at n=38A359964