28104

Appears in sequences

• Sum of first prime(n) primes.at n=27A022094
• Triangle read by rows: T(n,k) is the number of binary sequences of length n containing k subsequences 001 (n,k>=0).at n=53A118424
• Terms of A007504 divisible by 3.at n=34A249679
• Number of length-4 0..n arrays with no repeated value differing from the previous repeated value by other than one.at n=11A269538
• Number of 3Xn 0..1 arrays with no element equal to a strict majority of its horizontal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.at n=9A279743
• a(n) = Sum_{1 <= x_1 <= x_2 <= x_3 <= x_4 <= x_5 <= x_6 <= n} gcd(x_1, x_2, x_3 , x_4, x_5, x_6, n).at n=13A343520