20254
domain: N
Appears in sequences
- Fermat coefficients.at n=18A000970
- Molien series for cyclic group of order 5.at n=37A008646
- a(n) = floor(C(n,4)/5).at n=41A011795
- Schoenheim bound L_1(n,5,4).at n=36A036832
- a(n) = T(n,5), array T as in A051168; a count of Lyndon words; aperiodic necklaces with 5 black beads and n-5 white beads.at n=37A051170
- Number of nonprimes <= prime(n)^2.at n=35A053683
- Number of distinct partitions of triangular numbers n*(n+1)/2 into 3 parts for n>=1.at n=30A104385
- Principal diagonal of the convolution array A213781.at n=37A213782
- Number of totients up to 10^n.at n=5A221283
- a(n) = binomial(n+4,4)*gcd(n,5)/5.at n=37A234042
- a(n) = binomial(5n+6, 4)/5 for n >= 0.at n=7A238471
- The sum of denominators of unreduced mediants in Farey sequences of orders 1,2,..,n.at n=23A248832
- Array read by antidiagonals: T(n,k) = number of nonequivalent dissections of a polygon into n k-gons by nonintersecting diagonals up to rotation (k >= 3).at n=61A295224
- a(n) = Sum_{k=1..n} k^floor((n-k)/k).at n=28A344551
- Expansion of e.g.f. exp(2*x) / (3 - 2*exp(x)).at n=5A368319
- Squarefree numbers k such that k^2 is abundant, and d^2 is nonabundant for any proper divisor d of k.at n=38A381741
- Number of oriented polyominoes with n heptagonal cells of the hyperbolic regular tiling with Schläfli symbol {7,oo}.at n=7A389561