53789260175
domain: N
Appears in sequences
- a(n)^2 is a triangular number: a(n) = 6*a(n-1) - a(n-2) with a(0)=0, a(1)=1.at n=15A001109
- Indices of square numbers that are also hexagonal.at n=7A046176
- a(n) = (2*Pell(n+1) - (1+(-1)^n))/4.at n=29A105635
- a(2n) = A011900(n), a(2n+1) = A001109(n+1).at n=29A113225
- Expansion of (1-x)/((1-x)^2 - x^2*(1+x)^2).at n=29A116404
- a(n)=((2*Sqrt[2] + 3)^(2^(n - 1) - 1) - (3 - 2*Sqrt[2])^(2^(n - 1) - 1))/(4*Sqrt[2]).at n=4A139473
- a(n) = ((2*sqrt(2) + 3)^(2^(prime(n) - 1) - 1) - (3 - 2*sqrt(2))^(2^(prime(n) - 1) - 1))/(4*sqrt(2)).at n=2A139474
- Denominators of continued fraction convergents to sqrt(8/9).at n=15A144534
- a(n) = Product_{k=1..floor((n-1)/2)} (4 + 4*cos(k*Pi/n)^2).at n=30A152118
- Numerators b(n) of Pythagorean approximations b(n)/a(n) to sqrt(8).at n=13A195539
- Square roots of [A055872/8]: Their square written in base 8, with some digit appended, is again a square.at n=31A204512
- Expansion of (1 + 6*x + 17*x^2 - x^3 - 3*x^4)/(1 - 6*x^2 + x^4).at n=27A227792