28304

Appears in sequences

• Numbers k such that k divides the (left) concatenation of all numbers <= k written in base 15 (most significant digit on right and removing all least significant zeros before concatenation).at n=14A029532
• a(n) = ((4+sqrt(3))*(8+2*sqrt(3))^n-(4-sqrt(3))*(8-2*sqrt(3))^n)/(2*sqrt(3)).at n=4A161729
• Numbers k such that 8k+1, 12k+1 and 24k+1 are primes and the last two are also of the form x^2 + 27y^2, so the tetrahedral number T(24k+1) is a Fermat pseudoprime to base 2.at n=19A321867
• Array read by downward antidiagonals: A(n,k) = A(n-1,k+1) + (k+1)*Sum_{j=0..k} binomial(k, j)*A(n-1,j) with A(0,k) = 1, n >= 0, k >= 0.at n=31A370382