221760

Appears in sequences

• Highly composite numbers: numbers n where d(n), the number of divisors of n (A000005), increases to a record.at n=31A002182
• Where records occur in A038548.at n=28A004778
• a(1)=1; for n > 1, a(n) is the smallest number with the same number of divisors as 2*a(n-1).at n=20A019505
• Triangle read by rows giving number of rooted labeled trees with n >= 2 nodes and height d >= 1.at n=26A034855
• a(n) = n!*(2*n-5)/2.at n=5A034860
• a(n) is the minimal number of binary order n which has maximal number of divisors in this interval.at n=18A036484
• Triangle T(n,k) (0 <= k <= n) giving number of chains of length k in partially ordered set formed from subsets of n-set by inclusion.at n=43A038719
• a(n) = (n+3)*n!/2.at n=7A038720
• Triangular table of 2^n *(n+k)! / ((n-k)! * k! * 4^k).at n=39A043302
• Triangle T(n,k) (n >= 1, 0<=k<=n) giving number of preferential arrangements of n things beginning with k (transposed, then read by rows).at n=37A054255
• McKay-Thompson series of class 25A for Monster.at n=43A058594
• Numbers with an increasing number of nonprime divisors.at n=38A059992
• Consider the subsets of proper divisors of a number that sum to the number. These are numbers that set a record number of such subsets.at n=29A065218
• Numbers k that are repdigits in more bases (smaller than k) than any smaller number.at n=30A066044
• a(1) = 1; for n >= 2, suppose a(n-1) = Product p_i^e_i and n = Product p_i^f_i, then a(n) = Product p_i^(e_i*f_i).at n=10A072181
• a(1) = 1, a(n) = a(n-1) times smallest prime factor of n.at n=11A072486
• Least k such that n*prime(k) <= k*tau(k).at n=11A073066
• Highly composite numbers k such that 2*k is not a highly composite number.at n=10A073771
• a(n) = [n/1][n/2][n/3] ...[n/n] / n^(tau(n)/2).at n=22A076891
• Product of the smallest prime divisors of composite numbers between successive primes.at n=45A076976