65880

Appears in sequences

• Numbers k such that the value pi(k), the number of primes <= k, can be obtained deleting some of the repeating adjacent digits of k.at n=28A113898
• Number of different ways to select n elements from four sets of n elements under the precondition of choosing at least one element from each set.at n=5A115111
• 1000-gonal numbers: a(n) = n*(499*n - 498).at n=12A195163
• Triangle T(n,m) for the number of ways to put n stones into an m X n square grid such that each of the m rows contains at least one stone.at n=18A259051
• a(n) = (5/128)*n^4*(n mod 2) + (((-5/128)*n^4*(n mod 2) - 26) mod n) + n^3 (n > 0).at n=30A294264
• Numbers i such that Fibonacci(i) is divisible by i, i+1, i+2, and i+3.at n=22A298685
• a(n) = Sum_{d|n} (2^d - (-1)^d)*phi(3*n/d).at n=14A306899
• Triangle read by rows: T(n, k) = (Sum_{i=0..n-k} (-1)^i * binomial(n-k, i) * A007559(n-i)) * n! / ((n-k)! * A007559(k)) for 0 <= k <= n.at n=25A372921
• G.f. A(x,y) satisfies 1/x = Sum_{n=-oo..+oo} A(x,y)^n * (A(x,y)^n + y)^(n+1), as a triangle of coefficients T(n,k) of x^n*y^k in A(x,y), read by rows.at n=47A379200