401408

Appears in sequences

• 15-almost primes (generalization of semiprimes).at n=25A069276
• Numbers whose digital sum is equal to the sum of primes from their smallest to largest prime factor.at n=34A076406
• Initial values for f(x)=phi(sigma(x)) such that iteration of f ends in a cycle of length 18.at n=0A096890
• Triangle read by rows: T(n, m) = number of painted forests on labeled vertex set [n] with m trees. Also number of painted forests with exactly n - m edges.at n=29A106834
• Numbers of isomers of unbranched a-4-catapolypentagons - see Brunvoll reference for precise definition.at n=13A121135
• Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 7.at n=3A123802
• Row sums of triangle A133085.at n=15A133086
• Numerators of the terms of Lehmer's series S_2(2), where S_k(x) = Sum_{n>=1} n^k*x^n/binomial(2*n, n).at n=13A259852
• Triangle read by rows, T(n, k) = [x^k] p(n), where p(n) = 4^n * hypergeom([1/2, -n - 1, -n], [2, 2], x).at n=30A367022