30733

Appears in sequences

• Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 13.at n=30A051978
• a(0)=1, a(1)=1, a(n) = 13*a(n/2) for n=2,4,6,..., a(n) = 12*a((n-1)/2) + a((n+1)/2) for n=3,5,7,....at n=21A116524
• Positive numbers y such that y^2 is of the form x^2+(x+47)^2 with integer x.at n=12A159750
• Q-residue of A049310 (triangle of coefficients of Fibonacci polynomials), where Q=Pascal's triangle. (See Comments.)at n=9A193664
• Stellated octagon numbers: a(n) = 20*n^2 + 8*n + 1.at n=39A381196