99990000

Appears in sequences

• Numbers k such that k*(k+2) gives the concatenation of two numbers m and m-2.at n=6A116273
• Number of 10-ary sequences with primitive period n.at n=8A218127
• Number of length 8 primitive (=aperiodic or period 8) n-ary words.at n=10A218131
• a(n) = 100^n - 10^n.at n=4A276352
• Oblong (or pronic) numbers of the form x_n.y_n where z_n indicates the digit z repeated n times.at n=15A289980