43701901

Appears in sequences

• a(n+1) - 3*a(n) + a(n-1) = (2/3)(1+w^(n+1)+w^(2n+2)), where w = exp(2 Pi I / 3).at n=19A071618
• Expansion of x*(1+3*x+2*x^2)/((1+x+x^2)*(1-x-x^2)).at n=37A100886
• Expansion of (1-x)*(2*x^2+2*x+1) / ((x^2-x-1)*(x^2+x+1)).at n=37A111734
• a(n) = F(n-th squarefree)/product{p=primes,p|(n-th squarefree)} F(p), where F(m) is m-th Fibonacci number.at n=34A115022
• a(n) = 3*a(n-1) + 5*a(n-2) + a(n-3).at n=12A120775
• a(n) = floor(Lucas(n+1)/2), Lucas(n) = A000032(n).at n=37A173714
• Partial sums of odd Fibonacci numbers (A014437).at n=24A174542
• a(n) = numerator of Sum_{i=1..n} binomial(2n-i-1,i-1)/i.at n=18A175385
• Half the number of n X 2 binary arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.at n=18A185828
• a(n) = numerator of B(0,n) where B(n,n) = 0, B(n-1,n) = 1/n, and B(m,n) = B(m-1,n+1) - B(m-1,n).at n=37A189731
• Expansion of (1-x+x^3)/(1-x^2+2*x^3-x^4).at n=38A226447
• The edge independence number of the Lucas cube Lambda(n).at n=38A245968
• Indices of triangular numbers (A000217) that are also centered pentagonal numbers (A005891).at n=12A254626
• Smallest nonnegative integer not expressible by the addition and subtraction of fewer than n Lucas numbers.at n=13A364754