1855077841

Appears in sequences

• Pell-Lucas numbers: numerators of continued fraction convergents to sqrt(2).at n=25A001333
• NSW numbers: a(n) = 6*a(n-1) - a(n-2); also a(n)^2 - 2*b(n)^2 = -1 with b(n) = A001653(n+1).at n=12A002315
• Expansion of (1+x)/(1-2*x-x^2).at n=24A078057
• a(1) = 1, a(2) = 2; a(2*k) = 2*a(2*k-1) - a(2*k-2), a(2*k+1) = 4*a(2*k) - a(2*k-1).at n=24A084068
• Expansion of e.g.f.: cosh(sqrt(2)*x)*(1+exp(x)).at n=25A088014
• Composite NSW numbers.at n=7A094666
• Expansion of (1+2*x-2*x^3-3*x^2)/((x-1)*(x+1)*(x^2+2*x-1)).at n=24A100828
• Interlaces "2*n^2 - 1 is a square" with NSW numbers.at n=25A104683
• a(2n) = A002315(n), a(2n+1) = A082639(n+1).at n=24A113224
• Logarithmic derivative of the g.f. of A113281.at n=24A113282
• Shifted Pell recurrence: a(n) = 2*a(n-2) + a(n-4).at n=47A135246
• A005319 and A002315 interleaved.at n=25A143608
• Expansion of (1+6*x+x^2-2*x^3)/((x^2+2*x-1)*(x^2-2*x-1)), bisection is NSW numbers.at n=24A159582
• a(n) = if n even then P((n-2)/2)+P(n/2) otherwise 3*P((n+1)/2)+P((n-1)/2) where P(i) are the Pell numbers (A000129).at n=46A189050
• Bases b for which there exists an integer y such that y^2 in base b consists of 4 identical digits.at n=29A290204
• Numerators of the best approximations for sqrt(2).at n=36A331115