159600

Appears in sequences

• a(n) = n*(n-1)^2*(n-2).at n=19A047928
• Numbers n such that core(n)=floor(sqrt(n)), where core(x)=A007913(x) is the squarefree part of x and floor(sqrt(x))=A000196(x).at n=26A069186
• Group the triangular numbers so that the n-th group sum is a multiple of n. 1, (3, 6, 10, 15), (21), (28), (36, 45, 55, 66, 78), (91, 105, 120, 136, 153, 171, 190), ... Sequence contains the group sums.at n=18A114031
• Number of reduced words of length n in Coxeter group on 21 generators S_i with relations (S_i)^2 = (S_i S_j)^3 = I.at n=4A162807
• A Galton triangle: T(n,k) = (2k-1)*(T(n-1,k) + T(n-1,k-1)): a type B analog of the ordered Bell numbers A019538.at n=24A186695
• Triangular array read by rows: T(n,k) is the number of ordered set partitions of {1,2,...,n} with exactly k singletons, n>=0, 0<=k<=n.at n=40A187784
• Oblong numbers that are the product of two oblong numbers.at n=24A188660
• Numbers k such that the square part of k is one greater than the squarefree part of k.at n=7A189883
• Numbers with prime factorization pqrs^2t^4.at n=19A190384
• Least number, m, such that m^2 is expressible in just n ways as (p+1)(q+1) where p and q are distinct primes.at n=48A274877
• Crossing number of the n-crown graph (conjectured).at n=41A307182
• Number of edges in the hyperoctahedral (or cocktail party) graph of order n.at n=19A368757
• a(n) is the smallest positive integer k for which there is an identity of the form k*x = Sum_{i=1..m} k_i*g_i(x)^n where k_1, ..., k_m are in Z and g_1(x), ..., g_m(x) are in Z[x].at n=39A370252
• Oblong numbers that are products of smaller oblong numbers.at n=31A374374