21527

Appears in sequences

• Triangles in open triangular matchstick arrangement (triangle minus one side) of side n.at n=44A045947
• Smallest k not a palindrome and not divisible by 10 such that k and R(k) (A004086) both are divisible by the n-th prime.at n=26A075605
• Triangle T(n,m) = sum_{k=m..n} A001263(k,m).at n=59A104711
• a(n) = n*(4*n^2 + n - 1)/2.at n=21A125200
• Number of partitions of n not containing 4*(number of parts) as a part.at n=36A238492
• Sum of the next to smallest parts in the partitions of 4n into 4 parts with smallest part = 1.at n=32A239195
• Numbers k such that 2*k + 1 divides 2^(k+1) - 1.at n=15A246648
• Expansion of x*(1 - x - x^3)/((1 - x)*(1 - 2*x - 3*x^2 - 2*x^3 - x^4)).at n=10A274203
• Expansion of Sum_{i>=1} x^(i^3) / (1 - Sum_{j>=1} x^(j^3))^2.at n=37A281809
• Expansion of (q*j(q))^(11/24) where j(q) is the elliptic modular invariant (A000521).at n=2A289305
• Numerators of rational coefficients which are ratio of Brent's coefficients -A[n,2]/A343480.at n=23A380947
• Number of solid partitions of n with 4 parts.at n=42A387997
• Smallest numbers k such that 2^k-1 when written in ternary contains its least significant zero in position n.at n=28A391268