9018009

Appears in sequences

• Squares of elements to right of central element in Pascal triangle (by row) that are not 1.at n=36A014720
• Squares of odd elements in Pascal triangle that are not 1.at n=32A014725
• Squares of odd elements in Pascal triangle that are not 1.at n=33A014725
• Squares of numbers in array formed from odd elements to the right of middle of rows of Pascal triangle that are not 1.at n=15A014760
• Squares of numbers in array formed from odd elements to the right of middle of rows of Pascal triangle that are not 1.at n=20A014760
• Squares of numbers in array formed from odd elements to the right of middle of rows of Pascal triangle.at n=28A014761
• Squares of numbers in array formed from odd elements to the right of middle of rows of Pascal triangle.at n=34A014761
• Squares of odd hexagonal numbers.at n=19A014771
• a(1) = 1, then least square such that every partial concatenation is a prime.at n=37A090257
• Binomial(n-k,k)^2 where k = ceiling(n/4).at n=20A171001
• Binomial(n-k,k) * binomial(n-k-1,k+1) where k = ceiling(n/4).at n=19A171002
• Binomial coefficients: a(n) = binomial(3*n,n)^2.at n=5A188662
• a(n) is the number of subsets of {1..n} that contain 5 even and 5 odd numbers.at n=30A331576
• The number of walks of length 2n on the square lattice that start from the origin (0,0) and end at the vertex (2,0).at n=6A337900
• Squares of the form k + reverse(k) for at least one k.at n=29A358880
• a(n) = binomial(n, floor((n-1)/2))^2.at n=14A378060
• Odd numbers k that are closer to being perfect than previous terms and also satisfy the conditions that sigma(k) preserves the 3-adic valuation of k, and that sigma(k) == -k (mod 3).at n=13A386420
• a(n) = denominator((2^n*(n!)^2/(1+2*n)!)^2).at n=6A392619