39999

Appears in sequences

• Numbers having four 9's in base 10.at n=3A043528
• Smallest number whose sum of digits is n.at n=39A051885
• a(n) = n*10^n - 1.at n=3A064756
• Smallest composite number with digit sum n.at n=38A067524
• Squarefree numbers k with largest prime factor = floor(sqrt(k)).at n=33A071311
• a(n) is the smallest composite number with the sum of digits = the n-th composite number.at n=25A073866
• a(n) = smallest k such that 2k has digit sum = n.at n=41A077491
• a(n) = smallest k such that 5k has a digit sum = n.at n=41A077492
• Smallest number beginning with n and having a digit sum n.at n=38A077726
• Squarefree numbers of the form (prime(k)+1)*(prime(k+1)+1)/4.at n=17A079095
• Triangle T(n,k) = 10^(n-1) -1 + k*floor(9*10^(n-1)/(n+1)), with 1 <= r <= n, read by rows.at n=11A093850
• Smallest number whose sum of digits is 2n+1.at n=19A131668
• Smallest number whose sum of digits is 3n.at n=13A133195
• Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0) and consisting of n steps taken from {(-1, -1), (-1, 0), (0, -1), (0, 1), (1, -1), (1, 0)}.at n=8A151297
• a(1)=0, a(n+1) is the smallest nonprime with sum of digits > sum of digits of a(n).at n=35A156673
• a(n) = 64*n^2 - 1.at n=24A158684
• The smallest composite number larger than the n-th composite number, which has a sum of digits equal to the n-th composite number.at n=25A161551
• The smallest number larger than n with digital sum equal to n.at n=38A161561
• a(n) = 4*10^n - 1.at n=4A198970
• Smallest odd number with digit sum equal to n.at n=38A205960