221212

Appears in sequences

• n expressed in Fibonacci binary-like number system using only 1's and 2's.at n=32A108960
• A doubly-fractal simple sequence. Erase the first (leftmost) digit of every integer: what is left is the sequence itself. The erased digits, one by one, form also the sequence itself.at n=11A127303
• Numbers for which the sum of reciprocals of square of digits is an integer.at n=22A182452
• Shortest (x+1,2x)-code of n.at n=21A233135
• Reversed shortest (x+1,2x)-code of n.at n=27A233137
• Number of n X n 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.at n=6A281049
• Number of nX7 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.at n=6A281055
• Number of 7Xn 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.at n=6A281062
• a(n) = 54*2^n + 28 (n >= 1).at n=11A304606