87617

Appears in sequences

• Consider the mapping f(a/b) = (a^2+b^2)/(a^2-b^2) from rationals to rationals. Starting with 2/1 (a=2, b=1) and applying the mapping to each new (reduced) rational number gives 2/1, 5/3, 17/8, 353/225, ... . Sequence gives values of the numerators.at n=4A081465
• n times n+5 gives the concatenation of two numbers m and m+3.at n=8A116310
• a(n) = 64*n^2 + 1.at n=37A158686
• Numbers of the form n^2 + 1 without prime divisors of the form a^2 + 1.at n=29A217279
• Number of nX3 0..1 arrays with every element equal to 2, 3, 4, 5 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=10A301395