70722
domain: N
Appears in sequences
- Number of twin Pythagorean triples with hypotenuse less than 10^n.at n=9A101903
- G.f. satisfies: A(x) = Series_Reversion( x - 3*A(x)*B(x)^2 ), where B'(x) = 2*A(x).at n=4A259268
- Numbers k such that sigma(phi(k)) - phi(k) = phi(sigma(k)), where phi(k) is the Euler totient function of k and sigma(k) is the sum of the divisors of k.at n=16A271633
- Solutions x to the negative Pell equation y^2 = 72*x^2 - 83232 with x,y >= 0.at n=14A281239
- Number of nX3 0..1 arrays with no 1 equal to more than one of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly two elements.at n=6A282964
- Number of nX7 0..1 arrays with no 1 equal to more than one of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly two elements.at n=2A282968
- T(n,k)=Number of nXk 0..1 arrays with no 1 equal to more than one of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly two elements.at n=38A282969
- T(n,k)=Number of nXk 0..1 arrays with no 1 equal to more than one of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly two elements.at n=42A282969