178956971
domain: N
Appears in sequences
- Jacobsthal sequence (or Jacobsthal numbers): a(n) = a(n-1) + 2*a(n-2), with a(0) = 0, a(1) = 1; also a(n) = nearest integer to 2^n/3.at n=29A001045
- a(2*n) = 2*a(2*n-1), a(2*n+1) = 2*a(2*n)-1.at n=29A005578
- a(n) = (2^(2*n + 1) + 1)/3.at n=14A007583
- Number of Barlow packings with group P3(bar)m1(SO) that repeat after 2n-1 layers.at n=29A011950
- Cyclotomic polynomials at x=-2.at n=29A020501
- a(n) = C(n,0) + C(n,3) + ... + C(n,3[n/3]).at n=29A024493
- a(n) = C(n,2) + C(n,5) + ... + C(n, 3*floor(n/3)+2).at n=29A024495
- a(n) = (lcm_{k=0..n} (2^k + 1))/(lcm_{k=0..n-1} (2^k + 1)).at n=28A066845
- Let u(1)=u(2)=u(3)=2, u(n)=(1+u(n-1)u(n-2))/u(n-3); then a(n) is the numerator of u(n).at n=30A076737
- Expansion of 1/((1-x)*(1+2*x)).at n=28A077925
- Triangular array read by rows: row s contains integers of the form (2^s+1)/(2^r+1) in order of increasing r <= s-1.at n=32A079665
- A Jacobsthal number sequence.at n=9A082365
- a(n) = 2^n - A081374(n).at n=27A083322
- Jacobsthal reverse-pair sequence.at n=30A084183
- Generalized mod 3 multiplicative Jacobsthal sequence.at n=29A087462
- Generalized multiplicative Jacobsthal sequence.at n=29A087463
- Generalized Jacobsthal sequence.at n=28A087629
- Pair reversal of Jacobsthal numbers.at n=28A092808
- Expansion of (1 - 2*x + 2*x^2)/((1 - x^2)*(1 - 2*x)).at n=28A097072
- Sylvester-Jacobsthal cyclotomic numbers.at n=28A105603