1601145

Appears in sequences

• a(n) = (6*n+1)*(6*n+3)*(6*n+5).at n=19A001520
• a(n) = A081537(n)/A081535(n), with a(2) = 1 by convention.at n=17A081538
• Denominator of b(n) = -Sum_{k=1..n} A037861(k)/((2*k)*(2*k+1)), where A037861(k) = (number of 0's) - (number of 1's) in the binary representation of k.at n=10A110626
• Denominator of b(n) = -Sum_{k=1..n} A037861(k)/((2*k)*(2*k+1)), where A037861(k) = (number of 0's) - (number of 1's) in the binary representation of k.at n=11A110626
• Odd numbers k such that k and phi(k) have the same number of divisors.at n=11A116518
• a(n) = (4*n+3)*(4*n+5)*(4*n+7).at n=28A133767
• Least k with precisely n partitions k = x + y satisfying x > 0 and k' = x' + y', where k', x', y' are the arithmetic derivatives of k, x, y.at n=21A212664
• a(n) = (1/(2*n+1)) * Sum_{k=0..n} k^2 * (2*k+1) * binomial(3*n-k,n-k).at n=9A390971