47740

Appears in sequences

• Even numbers k such that the central binomial coefficient A000984(k, k/2) is divisible by k^2.at n=27A080395
• Number of ways to place 2 queens on an n X n chessboard so that they attack each other.at n=30A144945
• Long leg B of primitive Pythagorean triangles such that perimeters are Averages of twin prime pairs, q=p+1, a=q^2-p^2, c=q^2+p^2, b=2*p*q, s=a+b+c, s-+1 are primes.at n=16A155174
• Numbers k such that w(k-2), w(k-1), and w(k) are all odd, where w is A336957.at n=18A338070
• a(n) is the number in the first column of the Trithoff (tribonacci) array that starts off the row containing the tail of n times the tribonacci sequence.at n=27A351689
• Expansion of the continued fraction 1 / (1-q / (1-q-q^3 / (1-q-q^3-q^5 / (1-q-q^3-q^5-q^7 / (...))))).at n=14A355046
• Numbers k such that all primes dividing the k-th composite number divide k as well.at n=42A368309
• Antidiagonal-sums of the absolute value of the array A377046(n,k) = n-th term of k-th differences of nonsquarefree numbers (A013929).at n=16A377048