51005

Appears in sequences

• Number of subsequences of [ 1,...,n ] in which each even number has an odd neighbor.at n=17A007481
• a(n) = 3*a(n-1) + 2*a(n-2), with a(0)=2, a(1)=7.at n=8A007484
• Composite numbers k such that sigma(k) / d(k) is prime.at n=30A048969
• Sum of n-th row of A081930.at n=4A081932
• T(n,k)=Half the number of nXk binary arrays with no 1 having an adjacent 1 both above and to its left.at n=46A184761
• T(n,k)=Number of nXk 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than two of its immediate leftward or upward or left-upward diagonal neighbors.at n=46A208269
• (10^n)-th primitive antiharmonic number.at n=2A228036
• The sum of the totatives of n is a perfect cube.at n=38A237282
• Numbers of the form p^2*q, with odd primes p > q, such that q divides p-1.at n=26A350638
• Numbers k such that sigma(k) = psi(k) + tau(k).at n=47A387953