1940450

Appears in sequences

• a(n) = floor( a(n-1)/(sqrt(2) - 1) ), with a(0) = 1.at n=17A024537
• Numbers k such that k*(k - 1)/2 is a square.at n=9A055997
• Solutions k to the Diophantine equation k = 2n^2 = m^2+1.at n=4A088920
• Expansion of g.f. (1-x-x^2)/(1-x-3*x^2-x^3).at n=18A097075
• a(n) = 2*A079291(n) (twice squares of Pell numbers).at n=9A114619
• Consider all Pythagorean triples (X,X+1,Z) ordered by increasing Z; sequence gives Z-X values.at n=8A115599
• Binomial transform of 1,0,1,0,2,0,4,0,8,0,16,...at n=18A171842
• Number of 4 X n 0..1 arrays with every element equal to 0, 2, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=19A303326