9899999901domain: NAppears in sequencesNontrivial reversal numbers (numbers which are integer multiples of their reversals), excluding palindromic numbers and multiples of 10.at n=21A031877Inverse modulo 2 binomial transform of 10^n.at n=10A100681Numbers (not ending in 0) which are 9 times their digit-reversal.at n=10A222814