9090909

Appears in sequences

• a(n) = 9*a(n-1) + 10*a(n-2).at n=8A015585
• a(n) = floor(10^8/n).at n=10A033424
• a(n) = Smallest nontrivial number k > 9 such that |first (leftmost) decimal digit of k - second digit + third digit - fourth digit ...| = n.at n=36A060982
• Smallest number m such that first digit - second digit + third digit - fourth digit ... (of m) = n.at n=36A061479
• a(n) = Smallest nontrivial number k > 9 such that first (leftmost) digit - second digit + third digit - fourth digit ... of k = n.at n=36A061882
• a(n) = (n+1)^(n-1)/(n+2) + (-1)^n/(n+2).at n=9A083063
• n times n+9 gives the concatenation of two numbers m and m-8.at n=11A116240
• Numbers n such that the decimal digits of n are not present in k*n, k=2..9.at n=21A175637
• Numbers with the property that all pairs of consecutive digits differ by 9.at n=14A198486
• Integers n such that n, 2n, 3n ... 10n contain almost equally many copies of each base 10 digit.at n=7A267795
• Positive integers n (with k digits) such that if a positive integer m with k+1 digits is divisible by n, then all the rotations of m are divisible by n.at n=23A360423
• Proceeding from left to right, between any two consecutive digits (d_i, d_i+1) of an integer k, write down apart the lacking consecutive digits, in increasing order if d_i <d_i+1 or decreasing order if d_i>d_i+1. If abs(d_i - d_i+1) = 0 or 1 no digit is added. Sequence lists integers k that divide such resulting numbers.at n=11A381732