2744210

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=18A000129
• a(n) = 6*a(n-1) - a(n-2) for n > 1, a(0)=0 and a(1)=2.at n=9A001542
• Interleave denominators (A000129) and numerators (A001333) of convergents to sqrt(2).at n=36A002965
• The next smallest pair of numbers is taken so that a(2n-1)/a(2n) converges to sqrt(2).at n=51A065375
• 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=15A069306
• a(1) = 1, a(2) = 2; a(2*k) = 2*a(2*k-1) - a(2*k-2), a(2*k+1) = 4*a(2*k) - a(2*k-1).at n=17A084068
• Expansion of (3 -4*x -3*x^2)/((1-x^2)*(1-2*x-x^2)); a Pellian-related sequence.at n=17A114647
• a(n) = 6*a(n-4) - a(n-8).at n=36A116558
• Numbers k such that 2*k^2+1 is a perfect power.at n=10A117547
• a(n) = 6*a(n-2) - a(n-4) for n > 4, with a(1)=1, a(2)=0, a(3)=3, a(4)=2.at n=19A126354
• a(2n) = A001542(n+1), a(2n+1) = A038761(n+1); a Pellian-related sequence.at n=16A129345
• Pell numbers A000129 with 0 instead of last digit.at n=18A131726
• Repeat Pell numbers A000129.at n=36A135153
• Repeat Pell numbers A000129.at n=37A135153
• A trisection of A000129, the Pell numbers.at n=6A142588
• List of pairs: first pair is (1,1); then follow (x,y) with (x+2y, x+y).at n=35A155046
• Pell numbers sandwiched between two numbers having same number of divisors.at n=2A171669
• Square roots of [A055872/8]: Their square written in base 8, with some digit appended, is again a square.at n=20A204512
• a(n) = 2*a(n-1) + a(n-2) for n > 2, a(0) = a(1) = 1, a(2) = 2.at n=18A215928
• a(n+8)+34*a(n+4)+a(n)=0 with a(0)-a(7) as shown.at n=16A259861