18165

Appears in sequences

• a(n) = n*(n + 1)*(n^2 - 3*n + 6)/8.at n=19A004255
• Duplicate of A004255.at n=20A101357
• Difference between n-th prime squared and n-th perfect square.at n=33A106588
• Numbers n such that P(4n) is prime, where P(m) is the number of partitions of m.at n=43A111045
• Triangle read by rows: T(n,k) is the number of permutations of [n] having k cycles with at most 2 alternating runs (it is assumed that the smallest element of the cycle is in the first position), 0<=k<=n.at n=50A187247
• Antidiagonal sums of the convolution array A213783.at n=27A213760
• a(n) = n*(21*n-17)/2.at n=42A226491
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 323", based on the 5-celled von Neumann neighborhood.at n=30A271255
• Expansion of e.g.f. exp(1 - exp(x)*(1 - 2*x)).at n=7A307996
• Number of non-isomorphic multiset partitions of weight n whose incidence matrix has all distinct entries.at n=30A321662
• a(n) is the least number k such that there are exactly n pairs (p,q) of primes with p<q such that p+q = 2*k and that 2*k+p, 2*k+q, p*q-2*k and p*q+2*k are primes.at n=18A354462