18502

Appears in sequences

• G.f.: x*(1-x^2)*(x^4+x^3-x^2+x+1) / (x^8-4*x^6-x^4-4*x^2+1).at n=15A005822
• a(n+1) = a(n)-th composite number, with a(0) = 1.at n=38A006508
• Numbers n such that 197*2^n-1 is prime.at n=25A050850
• Numbers k such that 289*2^k + 1 is prime.at n=8A053361
• Number of connected squarefree graphs on n nodes.at n=10A077269
• Number of reverse alternating fixed-point-free permutations on n letters.at n=9A129815
• Triangle of coefficients from a polynomial recursion with row sum near =2*5^n: p(x,n)=(x + 1)*(p(x, n - 1) + 2*5^(n - 2)*(x + 5*x^Floor[n/2] + x^(n - 2))).at n=33A153354
• Triangle read by rows: T(n,k) is the number of reverse alternating (i.e., up-down) permutations of {1,2,...,n} having k fixed points (n >= 0, 0 <= k <= 1 + floor(n/2)).at n=37A162980
• Triangle read by rows: T(n,k) is the number of reverse alternating (i.e., up-down) permutations of {1,2,...,n} having k fixed points (n >= 0, 0 <= k <= 1 + floor(n/2)).at n=38A162980
• The consecutive squares of numbers multiplied by their next consecutive integer.at n=19A193608
• a(n) = 22*n^2.at n=29A195323
• T(n,k)=Number of nXk arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, without 2-loops or left turns.at n=37A221890
• Number of 2 X n arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, without 2-loops or left turns.at n=7A221891
• Number of nX3 0..2 arrays with rows and columns unimodal and antidiagonals nondecreasing.at n=4A224052
• Number of nX5 0..2 arrays with rows and columns unimodal and antidiagonals nondecreasing.at n=2A224054
• T(n,k)=Number of nXk 0..2 arrays with rows and columns unimodal and antidiagonals nondecreasing.at n=23A224057
• T(n,k)=Number of nXk 0..2 arrays with rows and columns unimodal and antidiagonals nondecreasing.at n=25A224057
• Coordination sequence for (2,5,infinity) tiling of hyperbolic plane.at n=21A265068
• Triangle T(n,k) read by rows: number of squarefree graphs on n nodes with k components.at n=67A300756
• Number of length-n binary words such that every conjugate (cyclic shift) is rich.at n=17A306316