1372105

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=9A001109
• Denominators of continued fraction convergents to sqrt(8).at n=17A041011
• Denominators of continued fraction convergents to sqrt(32).at n=17A041053
• Indices of square numbers that are also hexagonal.at n=4A046176
• a(n) = (2*Pell(n+1) - (1+(-1)^n))/4.at n=17A105635
• a(2n) = A011900(n), a(2n+1) = A001109(n+1).at n=17A113225
• Expansion of (1-x)/((1-x)^2 - x^2*(1+x)^2).at n=17A116404
• Dispersion of the sequence ([r*n] + 1: n >= 1), where r = 3 + 8^(1/2): square array D(n,m) (n, m >= 1), read by ascending antidiagonals.at n=44A120859
• Denominators of continued fraction convergents to sqrt(8/9).at n=9A144534
• a(n) = Product_{k=1..floor((n-1)/2)} (4 + 4*cos(k*Pi/n)^2).at n=18A152118
• Numerators b(n) of Pythagorean approximations b(n)/a(n) to sqrt(8).at n=7A195539
• Square roots of [A055872/8]: Their square written in base 8, with some digit appended, is again a square.at n=19A204512
• Expansion of (1 + 6*x + 17*x^2 - x^3 - 3*x^4)/(1 - 6*x^2 + x^4).at n=15A227792
• 256*n^8 - 448*n^6 + 240*n^4 - 40*n^2 + 1.at n=3A242853
• 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=42A357892