2100000

Appears in sequences

• Triangle of coefficients in expansion of (1+10x)^n.at n=33A013617
• Triangle of coefficients of certain polynomials (exponents in decreasing order).at n=49A033842
• Triangle whose (i,j)-th entry is binomial(i,j)*10^(i-j)*1^j.at n=30A038303
• 10th binomial transform of (0,0,1,0,0,0,...).at n=7A081140
• Members of A016052 whose digit sum is three.at n=31A119507
• Numbers m that raised to the powers from 1 to k (with k>=1) are multiple of the sum of their digits (m raised to k+1 must not be a multiple). Case k=16.at n=15A135201
• Inverse of A038303, and generalization of A130595.at n=30A165293
• Integers that can be generated with a C/C++ expression that is three or more characters shorter than their decimal representation.at n=20A168652
• Numbers k such that tau(sigma(k)) = rad(k).at n=30A173581
• Numbers n such that bigomega(n) = reversal(n).at n=6A181638
• Number of shapes of balanced 10-ary trees with n nodes, where a tree is balanced if the total number of nodes in subtrees corresponding to the branches of any node differ by at most one.at n=15A229395
• 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=26A281366
• Triangle read by rows: T(0,0) = 1; T(n,k) = T(n-1,k) + 10 * T(n-2,k-1) for k = 0..floor(n/2); T(n,k)=0 for n or k < 0.at n=47A317054
• Triangle read by rows: T(0,0) = 1; T(n,k) = 10*T(n-1,k) + T(n-2,k-1) for k = 0..floor(n/2); T(n,k)=0 for n or k < 0.at n=27A317055
• Ternary numbers consisting of a run of 2's, then a run of 1's, then a run of 0's.at n=20A371053
• Ternary numbers that are concatenated runs C(1)A(1)B(1)C(2)A(2)B(2)...C(k)A(k)B(k), where A(i) is a run of 1's, B(i) a run of 0's, and C(i) a run of 2's, for i = 1..k.at n=21A371111
• Numbers k such that (sigma(k) + sigma(k + sigma(k))) / k is an integer where sigma(k) = A000203(k) is the sum of the divisors of k.at n=38A383392