181500

Appears in sequences

• Composite numbers divisible by the palindromic sum of their palindromic prime factors (counted with multiplicity).at n=33A046366
• a(n) = 3!*n*S(n-1,3), where S denotes the Stirling numbers of second kind.at n=10A052761
• Triangular array read by rows. T(n,k) is the number of chain topologies on an n-set with exactly k open sets where one of the open sets is a single point set, n >= 2, 3 <= k <= n+1.at n=38A282507
• Composites c where an integer b with 1 < b < c exists such that when the k digits in the base-b expansion of c are considered as exponents in an ordered list of primes prime(1), prime(2), ..., prime(k), then Product_{i=1..k} prime(i)^d[i] = c, where d[h] gives the h-th most significant digit in the expansion.at n=29A307458
• Consider coefficients U(m,L,k) defined by the identity Sum_{k=1..L} Sum_{j=0..m} A302971(m,j)/A304042(m,j) * k^j * (T-k)^j = Sum_{k=0..m} (-1)^(m-k) * U(m,L,k) * T^k that holds for all positive integers L,m,T. This sequence gives 3-column table read by rows, where the n-th row lists coefficients U(2,n,k) for k = 0, 1, 2; n >= 1.at n=28A316349
• Expansion of 60*x*(1 + 4*x + x^2) / (1 - x)^5.at n=9A316458