4049540496domain: NAppears in sequencesSquares that are concatenations of two consecutive nonzero numbers.at n=6A030466Squares with an even number of digits, the respective halves of which are consecutive integers.at n=9A064014Number of 7Xn 0..1 arrays avoiding 0 0 1 and 0 1 1 horizontally and 0 0 1 and 1 1 0 vertically.at n=21A207407