81927

Appears in sequences

• Random walks (binomial transform of A006054).at n=9A005021
• Expansion of (1-x)/(1-x-2*x^2+x^3).at n=21A052547
• a(n) = (3/2)*a(n-1) if a(n-1) is even; (3/2)*(a(n-1)+1) if a(n-1) is odd.at n=25A070885
• Number of walks of length n on P_3 plus a loop at the end.at n=23A096976
• Numbers m such that pi(m) = prime(d_1*d_2*...*d_k) where d_1 d_2 ... d_k is the decimal expansion of m.at n=10A107120
• 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)=1. Then, a(n)=a(2*r+p_i) gives the quantity of H_(7,1,0) 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=44A187065
• 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_(7,2,0) 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=42A187066
• a(n) is the result of factoring a(n-1) + 1 into primes, replacing each prime 2 with a 3, and taking the product of the resulting factors.at n=13A242438
• a(n) = a(n-1) + a(n-2) if n is even and a(n) = a(n-3) + a(n-4) if n is odd, with a(0) = a(1) = a(2) = 0 and a(3) = 1.at n=45A265755