57965

Appears in sequences

• a(n) = 5*a(n-1) - a(n-2), with a(0) = 2, a(1) = 5.at n=7A003501
• Numerators of continued fraction convergents to sqrt(21).at n=13A041032
• Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 19.at n=31A051984
• A number triangle associated with the Chebyshev polynomials of the first kind.at n=58A101161
• Triangle, diagonals generated from Lucas polynomials.at n=47A118007
• a(1)=a(2)=1. a(n+1) = a(n) + a(smallest prime dividing n).at n=48A128216
• Array T(n,k) read by antidiagonals: T(n,k) = sum(i=0...n, (-1)^(n+i) * C(n+i,2i) * n/(2i+1) * k^(2i+1) ), n>0, k>1.at n=18A231123
• Numbers n such that phi(n) is a Fibonacci number.at n=42A280592
• Rectangular array A: first differences of row entries of array A294099, read by antidiagonals.at n=61A298675
• Array read by antidiagonals upwards: a(i,0) = 2, i >= 0; a(i,1) = i+2, i >= 0; a(i,j) = (i+2) * a(i,j-1) - a(i,j-2), for i >= 0, j > 1.at n=62A299741