6625109

Appears in sequences

• Pell numbers: a(0) = 0, a(1) = 1; for n > 1, a(n) = 2*a(n-1) + a(n-2).at n=19A000129
• Numbers k such that 2*k^2 - 1 is a square.at n=9A001653
• Interleave denominators (A000129) and numerators (A001333) of convergents to sqrt(2).at n=38A002965
• Primitive parts of Pell numbers.at n=18A008555
• Denominators of continued fraction convergents to sqrt(8).at n=18A041011
• a(n) is the least natural number m such that the fractional part of m*(2^0.5) is less than 2^(-n).at n=23A058580
• a(n) is the least natural number m such that the fractional part of m*(2^0.5) is less than 2^(-n).at n=22A058580
• Number of 2 X n binary arrays with a path of adjacent 1's from upper left corner to anywhere in right hand column.at n=16A069306
• Expansion of 1/(1 + 2*x - x^2).at n=18A077985
• a(0) = a(1) = 1; thereafter a(2*n+1) = 2*a(2*n) - a(2*n-1), a(2*n) = 4*a(2*n-1) - a(2*n-2).at n=19A079496
• Greedy frac multiples of sqrt(2): a(1)=1, Sum_{n>=0} frac(a(n)*x)=1 at x=sqrt(2).at n=26A079934
• a(0)=0; a(1)=1; a(2n) = 4*Sum_{k=0..n} a(2k-1); a(2n+1) = a(2n) + a(2n-1).at n=19A089499
• Denominator when the numerator of the continued fraction rational approximation of sqrt(2) is prime. Also the denominators of A086395(n).at n=7A101411
• Interlaces "2*n^2 - 1 is a square" with NSW numbers.at n=18A104683
• Pythagorean triples of nearly isosceles triangle.at n=26A114336
• a(n) = 6*a(n-4) - a(n-8).at n=35A116558
• a(n) = 6*a(n-4) - a(n-8).at n=38A116558
• a(n) = 6*a(n-4) - a(n-8).at n=37A116558
• a(2n) = A001653(n) (Numbers n such that 2*n^2 - 1 is a square), a(2n+1) = A038725(n+1).at n=18A117719
• Triangle T(n, k) = (k*ChebyshevU(n, (k+2)/2) + 2*ChebyshevT(n+1, (k+2)/2))/2.at n=31A121872