666666
domain: N
Appears in sequences
- Concatenate n n times.at n=5A000461
- a(n) = 6*(10^n - 1)/9.at n=6A002280
- Repdigit numbers, or numbers whose digits are all equal.at n=51A010785
- Numbers > 9 with all digits the same.at n=41A014181
- Palindromes of the form k*(k+5).at n=7A028559
- Repdigit + 1 is prime.at n=8A028988
- Palindromic in bases 10 and 16.at n=25A029731
- a(n) = floor(10^7/n).at n=14A033425
- Numbers with digits nondecreasing and their reciprocals sum to 1/(positive integer).at n=40A045910
- Replace each 1 in decimal expansion of n with 1 1's, each 2 with 2 2's, etc. (0 vanishes).at n=5A048376
- n times (n 1's): a(n) = n*(10^n - 1)/9.at n=6A053422
- Numbers n such that n and 2n-1 are both palindromes.at n=10A069882
- Worthless numbers: numbers without h, o, r, t, or w.at n=10A073419
- Number of Fibonacci numbers F(k), k <= 10^n, which end in 2.at n=6A073548
- Number of Fibonacci numbers F(k), k <= 10^n, which end in 6.at n=6A073549
- Nonsquarefree numbers obtained by repeating a single digit.at n=19A077572
- a(n) = smallest multiple of the n-th prime whose decimal expansion is nnn...n, or 0 if no such number exists.at n=5A078251
- LookAndSay(n) is palindromic.at n=29A079676
- Smallest multiple of n using all digits of (n-1) at least once and no others; or 0 if no such number exists.at n=6A083958
- Smallest multiple of n using all digits of (n-1) with the same frequency and no others; or 0 if no such number exists.at n=6A083959