18723

Appears in sequences

• Numbers k such that 6!*(2*k-7)!/(k!*(k-1)!) is an integer.at n=20A004786
• Numbers k such that 7!*(2k-8)!/(k!*(k-1)!) is an integer.at n=23A004787
• Numbers having four 4's in base 8.at n=19A043440
• 3p^2 where p runs through the primes.at n=21A079705
• Expansion of x*(1+3*x-4*x^2-5*x^3-4*x^6+4*x^5+3*x^4) / ((1+4*x^2)*(1+x^2)*(1-x^2+x^4)).at n=14A112523
• Triangle read by rows: T(n,k) is the number of deco polyominoes of height n and such that the sum of the bottom levels of all columns is k (n>=1, k>=0; informally, the number of the "missing" cells in the right bottom corner of the polyomino). A deco polyomino is a directed column-convex polyomino in which the height, measured along the diagonal, is attained only in the last column.at n=49A122104
• a(n) = (prime(n)^2 + prime(n+1))/2.at n=42A140511
• A three-dimensional version of the cellular automaton A160118, using cubes.at n=23A160119
• 3*h^2, where h is an odd integer not divisible by 3.at n=26A229852
• Number of length 3 0..n arrays with each partial sum starting from the beginning no more than sqrt(2) standard deviations from its mean.at n=29A244906
• Numbers whose cube is of the form a^5 + b^5 - c^5 with a >= b > 0 and c not in {a,b}.at n=5A257298
• The Hwang-Deutsch function f_3(n).at n=36A260996
• Number of partitions of n into parts with an odd number of distinct prime divisors.at n=58A285799
• First differences of A325056: distance in A076042 from n-th low point to the next.at n=16A324792
• Number of separable partitions of n in which the number of distinct (repeatable) parts is > 1.at n=37A325716
• Numbers k such that usigma(uphi(k)) = uphi(usigma(k)), where usigma is the sum of unitary divisors function (A034448) and uphi is the unitary totient function (A047994).at n=41A329730
• Numbers k such that p^2 divides k, where p = A006530(k), the largest prime factor of k, and sigma(k) does not have any prime factor larger than p.at n=23A336354
• Numbers that can be represented in more than one way as p^2+p*q+q^2 with p and q primes, p<=q.at n=16A349987
• Numbers of the form p^2*q, with odd primes p > q, such that q divides p-1.at n=16A350638