21040

Appears in sequences

• Expansion of Product_{m>=1} (1 - m*q^m)^7.at n=14A022667
• a(1)=1, a(n) = a(n-1) + n^3 if n odd, a(n) = a(n-1) + n^2 if n is even.at n=18A140154
• T(n,k) = 4*A046802(n,k) - 3*A007318(n,k), triangle read by rows (0 <= k <= n).at n=38A168289
• T(n,k) = 4*A046802(n,k) - 3*A007318(n,k), triangle read by rows (0 <= k <= n).at n=42A168289
• Coefficients of polynomials described below.at n=39A174531
• a(n) = Ann(2n) where Ann(n) is the number of annular non-crossing matchings with n total endpoints.at n=9A268042
• Number of integer partitions of n that are not pairwise coprime, where a singleton is not coprime unless it is (1).at n=37A335240
• Nonprime numbers k whose arithmetic derivative k' (A003415) is a Fibonacci number (A000045).at n=36A362141
• Expansion of e.g.f. exp(-2*x) / (1 - log(1 + x)).at n=9A368289
• Alternating sum of the numbers in the trajectory of n for the 3x+1 problem.at n=54A386437