18939904

Appears in sequences

• Expansion of (1 + 2*x)/(1 - 2*x)^3.at n=16A014477
• a(n) = 4^n*(2n + 1)^2.at n=8A164583
• Number of nX4 binary arrays without the pattern 0 1 0 diagonally or antidiagonally.at n=6A188905
• Number of nX7 binary arrays without the pattern 0 1 0 diagonally or antidiagonally.at n=3A188908
• Determinant of the (p_n-1) X (p_n-1) matrix with (i,j)-entry equal to the Legendre symbol ((i^2+6*i*j+j^2)/p_n), where p_n is the n-th prime.at n=5A225611
• Lexicographically least sequence of squares that are sum-free.at n=32A226076
• Product of numbers m with 2 <= m <= n whose prime divisors all divide n.at n=33A243103
• a(n) = the smallest number m such that gcd(m, tau(m)) = n where tau(k) = the number of the divisors of k (A000005).at n=16A324553
• a(n) = the smallest number m such that gcd(tau(m), pod(m)) = n where tau(k) = the number of the divisors of k (A000005) and pod(k) = the product of the divisors of k (A007955).at n=16A324555
• a(n) is the determinant of an n X n Hermitian Toeplitz matrix whose first row consists of 1, 2*i, ..., n*i, where i denotes the imaginary unit.at n=32A359559