20856

Appears in sequences

• Trajectory of 103 under the Reverse and Add! operation carried out in base 3, written in base 10.at n=7A077408
• Row sums in A083175.at n=21A083175
• C(n-3,3)+C(n-7,7)+...+C(n-(4*floor((n-4)/4)+3),4*floor((n-4)/4)+3).at n=24A101552
• Values of x in solutions (x,y,z) to the Diophantine equation x^3-x^2+y^3-y^2=z^3-z^2, with 1<x<y<z.at n=32A138667
• a(n) = prime(prime(prime(prime(n) - 1) - 1) - 1) - 1, where prime(n) is the n-th prime.at n=19A141217
• a(n) = 2*( a(n-5) + a(n-8) + a(n-11) ) for n >= 12.at n=42A226592
• a(n) = (8*n+13*n^3+3*n^5)/24; also the sum of triangular numbers taken in successive groups of increasing size (see Example).at n=10A260513
• Take apart the sides of each of the integer-sided 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=30A308233
• Number of permutations p of [n] such that | |p(i) - p(i-1)| - |p(i+1) - p(i)| | <= 1.at n=14A338765
• Expansion of e.g.f. 1 / (1 + 4 * log(1 - x))^(3/2).at n=4A375947