19544085

Appears in sequences

• Least positive integer k such that the fractional part of k*sqrt(5) has its n initial partial quotients all equal to 1.at n=17A004794
• a(n) = Sum_{k=0..floor(n/4)} binomial(n-2k,2k).at n=37A005252
• Expansion of (1+x)/((1+x+x^2)(1-x-x^2)).at n=36A093040
• a(n) = floor[(phi + n mod 2)*a(n-1)], a(1)=1.at n=25A107857
• a(n) = b(k), where b(k) = Fibonacci(n-1) and k = floor( n*(1+sqrt(5))/2 ).at n=25A107858
• a(n+3) = 3*a(n+2) + 5*a(n+1) + a(n), a(0) = 1, a(1) = 2, a(2) = 11.at n=12A110679
• Expansion of (1 + x)^2/((1 + x + x^2)*(1 + 3*x + x^2)).at n=18A113066
• a(n) = ceiling(Fibonacci(n)/2).at n=38A173173
• a(n) = (A000045(n)+A173432(n))/2.at n=37A173433
• Indices of centered pentagonal numbers (A005891) that are also triangular numbers (A000217).at n=12A254627
• a(n) = (Fibonacci(3*n-1) + 1)/2 for n >= 1.at n=12A292278
• Expansion of (1 - x + x^2)/((1 - x + x^2)^2 - 4*x^2).at n=18A376716
• Upper (1/2)-midsequence of (F(2n)) and (F(2n+1)), where F=A000045 (Fibonacci numbers); see Comments.at n=18A387779