64570081

Appears in sequences

• a(n) = (3^n - 1)/2.at n=17A003462
• Number of free subsets of multiplicative group of GF(3^n).at n=16A007231
• Cyclotomic polynomials at x=3.at n=17A019321
• Cyclotomic polynomials at x=-3.at n=34A020502
• a(n) = 2*a(n-1) + 3*a(n-2), a(0) = a(1) = 1.at n=17A046717
• Numbers that are repdigits in base 3.at n=33A048328
• a(n) = a(n-1) + 3*a(n-2) - 3*a(n-3), with a(0)=a(1)=1, a(2)=4.at n=32A052993
• a(n) = a(n-1) + 3*a(n-2) - 3*a(n-3), with a(0)=a(1)=1, a(2)=4.at n=33A052993
• a(n) = floor(9^9/n).at n=5A057071
• Zsigmondy numbers for a = 3, b = 1: Zs(n, 3, 1) is the greatest divisor of 3^n - 1^n (A024023) that is relatively prime to 3^m - 1^m for all positive integers m < n.at n=16A064079
• Binomial transform of Jacobsthal gap sequence (A080924).at n=17A080925
• a(n)=3*(3^prime(n)-1)/denominator(B(2*prime(n))) where prime(n)=n-th prime and B(k) denotes the k-th Bernoulli number.at n=4A090814
• Expansion of (1+3x)/((1-x^2)(1-3x^2)).at n=32A094025
• a(n) = (3*9^n - 1)/2.at n=8A096053
• Expansion of x*(1+x+2*x^3) / ((x-1)*(1+x)*(3*x^2-1)).at n=33A120463
• a(n) = 3*a(n-1) - a(n-3) + 3*a(n-4), with initial values 2,5,13,40.at n=16A133448
• First differences of A140298.at n=52A140313
• a(n) = (3^n-1)/2 if n odd, (3^n-1)/8 if n even.at n=17A152298
• a(n) = Sum_{d|n} Moebius(n/d)*d^(b-1)/phi(n) for b = 18.at n=2A161213
• a(n) = (3*3^n-(-1)^n)/2.at n=16A164907