21000000

Appears in sequences

• Triangle whose (i,j)-th entry is binomial(i,j)*3^(i-j)*10^j.at n=34A038228
• Triangle whose (i,j)-th entry is binomial(i,j)*10^(i-j)*3^j.at n=29A038305
• Denominator of Bernoulli(n, 1/10).at n=6A158994
• Denominator of Bernoulli(n, -1/10).at n=6A158996
• Denominator of Bernoulli(n, -3/10).at n=6A159012
• Concatenate the positions of digits 0, 1,..., 9 in the decimal representation of n, using 1 for the rightmost digit etc., and 0 when the digit does not occur.at n=23A260519
• Lexicographically least strictly increasing sequence such that, for any n>0, Sum_{k=1..n} a(k) can be computed without carries in base 10.at n=32A278742
• Lexicographically least strictly increasing sequence such that, for any n>0, Sum_{k=1..n} a(k) can be computed without carries in base 9 (the numbers are written in base 9).at n=30A281366
• Smallest number m such that tau(k) * k = m has exactly n solutions when tau(k) is the number of divisors of k.at n=3A338381