66922

Appears in sequences

• a(n) = 2*a(n-1) + a(n-2), with a(0) = 1, a(1) = 2, a(2) = 4.at n=13A052542
• Numbers k such that 2*k^2 - 4 is a square.at n=6A075870
• Series ratios converge alternately to sqrt(2) and 1+sqrt(1/2).at n=26A082766
• a(n) = (a(n-1) mod 2)*a(n-1) + a(n-2) with a(0)=0, a(1)=1.at n=39A097564
• Sylvester dividends for Pell numbers.at n=25A105606
• Numerators of "Farey fraction" approximations to sqrt(2).at n=27A119016
• Fixed-j dispersion for Q = 8: Square array D(g,h) (g, h >= 1), read by ascending antidiagonals.at n=34A120860
• Numerators of principal and intermediate convergents to 2^(1/2).at n=24A143607
• Numerators of the upper principal and intermediate convergents to 2^(1/2).at n=12A143609
• Numerators of fractions in a 'zero-transform' approximation of sqrt(2) by means of a(n) = (a(n-1) + c)/(a(n-1) + 1) with c=2 and a(1)=0.at n=13A163271
• a(n) = tau(n)*Pell(n), where tau(n) = A000005(n), the number of divisors of n.at n=12A204270
• a(n) = Pell(n)*A001227(n) for n >= 1, where A001227(n) is the number of odd divisors of n.at n=12A209445
• Two column recursive array A(n,k), relating expressions based on half-squares (A007590) to each other and several other sequences, read by rows.at n=41A227972
• List of triples (r,s,t): the matrix M = [[1,4,4][1,3,2][1,2,1]] is raised to successive powers, then (r,s,t) are the square roots of M[3,1], M[1,1], M[1,3] respectively.at n=41A249576
• List of triples (r,s,t): the matrix M = [[1,4,4][1,3,2][1,2,1]] is raised to successive negative powers, then (r,s,t) are the square roots of M[3,1], M[1,1], M[1,3] respectively.at n=36A249577
• Lexicographically earliest sequence of distinct positive integers with no finite subset summing to a positive Pell number (A000129).at n=29A354005