5374978561

Appears in sequences

• Numerators of continued fraction convergents to sqrt(5).at n=16A001077
• a(n) = 18*a(n-1) - a(n-2).at n=8A023039
• Numerators of continued fraction convergents to sqrt(20).at n=15A041030
• Numerators of continued fraction convergents to sqrt(45).at n=23A041076
• Numerators of continued fraction convergents to sqrt(80).at n=15A041142
• Numerators of continued fraction convergents to sqrt(180).at n=15A041332
• Numerators of continued fraction convergents to sqrt(245).at n=19A041458
• Numerators of continued fraction convergents to sqrt(320).at n=15A041604
• Numerators of continued fraction convergents to sqrt(405).at n=7A041768
• Numerators of continued fraction convergents to sqrt(720).at n=15A042386
• Numerators of continued fraction convergents to sqrt(980).at n=19A042896
• Expansion of x*(1 + x - 2*x^2) / ( 1 - 4*x^2 - x^4).at n=33A059973
• a(1)=1; for n > 2, a(n) is the smallest integer > a(n-1) such that frac(sqrt(5)*a(n)) < frac(sqrt(5)*a(n-1)).at n=30A079497
• Consider the mapping f(r) = (1/2)*(r + N/r) from rationals to rationals where N = 5. Starting with r = 2 and applying the mapping to each new (reduced) rational number gives 2, 9/4, 161/72, 51841/23184, ..., tending to N^(1/2). Sequence gives values of the numerators.at n=4A081459
• a(n) = (F(2*n-1) + F(2*n+1))*(5/6 - cos(2*Pi*n/3)/3), where F(n) = Fibonacci(n).at n=24A128052
• Numerators of continued fraction convergents to sqrt(5/4).at n=15A153316
• Pierce expansion of 144 - 64*sqrt(5).at n=7A219511
• 128*n^8 - 256*n^6 + 160*n^4 - 32*n^2 + 1.at n=9A243134
• a(n) = T(n,n+1) where T(n,x) is a Chebyshev polynomial of the first kind.at n=8A342205