7997214

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=10A001109
• Denominators of continued fraction convergents to sqrt(8).at n=19A041011
• a(n) = 34*a(n-1) - a(n-2); a(0)=0, a(1)=6.at n=5A082405
• a(n) = (2*Pell(n+1) - (1+(-1)^n))/4.at n=19A105635
• a(2n) = A011900(n), a(2n+1) = A001109(n+1).at n=19A113225
• Expansion of (1-x)/((1-x)^2 - x^2*(1+x)^2).at n=19A116404
• a(n) = Product_{k=1..floor((n-1)/2)} (4 + 4*cos(k*Pi/n)^2).at n=20A152118
• Square roots of [A055872/8]: Their square written in base 8, with some digit appended, is again a square.at n=21A204512
• Expansion of (1 + 6*x + 17*x^2 - x^3 - 3*x^4)/(1 - 6*x^2 + x^4).at n=17A227792
• a(n) = 512*n^9 - 1024*n^7 + 672*n^5 - 160*n^3 + 10*n.at n=3A242854
• a(n) = U(3*n, n), where U(n, x) is the Chebyshev polynomial of the second kind.at n=3A349074
• T(n,k) are the values of a variant of the Chebyshev polynomials P(n,x) of order n evaluated at x = k, where T(n,k), n >= 0, k <= n is a triangle read by rows. P(0,x) = 1, P(1,x) = x, P(n,x) = x*P(n-1,x) - P(n-2,x).at n=51A357892