49661

Appears in sequences

• a(n) = a(n-1) + 4*a(n-2), a(0) = a(1) = 1.at n=12A006131
• Strong pseudoprimes to base 6.at n=18A020232
• a(n) = (2*n+1)*(4*n^2+4*n+3)/3.at n=26A057813
• A partial product representation of A006131 and A072265.at n=25A072270
• Numbers k such that k and k^2 use only the digits 1, 2, 4, 6 and 9.at n=48A136995
• Positive numbers y such that y^2 is of the form x^2+(x+191)^2 with integer x.at n=11A161487
• Expansion of 1/(1-x*sqrt(1+4*x^2)).at n=24A190864