89509domain: NAppears in sequencesFirst differences of A213709.at n=20A226060Least number x such that x^n has n digits equal to k. Case k=4.at n=34A285451Records in A171898.at n=28A309813a(n) = Sum_{k=0..n} binomial(n+k,n-k) * Fibonacci(k+1).at n=10A389699