27260

Appears in sequences

• Number of n-node triangulations of the Klein bottle N_2 in which every node has degree >= 5.at n=6A129048
• First differences of A161762.at n=12A162460
• Totally multiplicative sequence with a(p) = 9p+2 for prime p.at n=29A166676
• The number of permutations avoiding simultaneously consecutive patterns 123 and 231.at n=9A173938
• a(n) = Sum_{k<=n} A007955(k) * A007955(n-k+1), where A007955(m) = product of divisors of m.at n=15A174938
• G.f.: exp( Sum_{n>=1} A132303(n)/3 * x^n/n ), where A132303(n) = sum of the cubes of the trinomial coefficients in row n of triangle A027907.at n=5A251686
• Take apart the sides of each of the integer-sided scalene triangles with perimeter n (at their vertices) and rearrange them orthogonally in 3-space so that their endpoints coincide at a single point. a(n) is the total volume of all rectangular prisms enclosed in this way.at n=35A308234
• a(n) = Sum_{k=0..floor(n/3)} (-1)^k * binomial(n-1-2*k,n-3*k) * binomial(2*k,k).at n=22A360314