21794

Appears in sequences

• Maximal length of rook tour on an n X n board.at n=31A006071
• Expansion of g.f. (1-x^2)/(1-x-2*x^2+x^3).at n=18A028495
• a(n) = (10*n^3 - 9*n^2 + 2*n)/3 + 1.at n=19A034721
• Numerators of continued fraction convergents to sqrt(430).at n=7A041818
• Expansion of (1-2*x)*(1-x)/(1-5*x+6*x^2-x^3).at n=9A052975
• Number of consecutive prime runs of 8 primes congruent to 1 mod 4 below 10^n.at n=8A092657
• Number of 12-almost primes 12ap such that 2^n < 12ap <= 2^(n+1).at n=24A120043
• First row of infinite array A(j,k): A(j,1) = j-1; A(1,k) = A(2,k-1); for j, k > 1, A(j,k) = A(j-1,k) - A(j+1,k-1) if that number is positive and not already in column k, A(j,k) = A(j-1,k) + A(j+1,k-1) otherwise.at n=23A140985
• Ulam's spiral (NNE spoke).at n=37A143861
• G.f.: -2*(-2 - 11*x - 4*x^2 + x^3)/(x - 1)^4.at n=15A152110
• Maximal length of rook tour on an n X n+2 board.at n=30A152133
• Let i be in {1,2,3} and let r >= 0 be an integer. Let p = {p_1, p_2, p_3} = {-2,0,1}, n = 2*r + p_i and define a(-2)=0. Then, a(n) = a(2*r + p_i) gives the quantity of H_(7,3,0) tiles in a subdivided H_(7,i,r) tile after linear scaling by the factor x^r, where x = sqrt(2*cos(Pi/7)).at n=37A187067
• Number of ordered triples (w,x,y) with all terms in {-n,...-1,1,...,n} and 2w+x+y>2.at n=18A211619
• Expansion of (1-x)*(1-2*x)*(1-3*x)/(1-9*x+28*x^2-35*x^3+15*x^4-x^5).at n=8A224509
• Numbers k such that 4*10^k + 87 is prime.at n=25A273097
• Number of palindromic compositions of n with parts in {1,2,4,6,8,10,...}.at n=37A276055
• Number of ways to split an n-cycle into connected subgraphs all having at least 4 vertices.at n=31A306351