666666666666
domain: N
Appears in sequences
- a(n) = 6*(10^n - 1)/9.at n=12A002280
- Numbers n such that n and 2n-1 are both palindromes.at n=16A069882
- Number of Fibonacci numbers F(k), k <= 10^n, which end in 2.at n=12A073548
- Number of Fibonacci numbers F(k), k <= 10^n, which end in 6.at n=12A073549
- Largest term in periodic part of continued fraction expansion of square root of n-th repunit.at n=23A096487
- a(n) is the least positive integer in base 10 containing n sixes that is divisible by n.at n=10A112902
- Numbers k such that the k-th triangular number contains only digits {1,2,4}.at n=21A119100
- Numbers k such that the k-th triangular number contains only digits {1,2,7}.at n=25A119106
- Numbers k such that the k-th triangular number contains only digits {1,2,9}.at n=19A119110
- Numbers k such that k and k^2 use only the digits 3, 4, 5 and 6.at n=11A137120
- Numbers k such that k and k^2 use only the digits 3, 4, 5, 6 and 8.at n=27A137122
- Conversion to octal of the binary expansion given by the first n terms of the period-3 sequence A011655 (repeat 0, 1, 1).at n=36A289006
- An explicit example of an infinite sequence with a(1)=1 and, for n >= 2, a(n) and S(n) = Sum_{i=1..n} a(i) have no digit in common.at n=23A308900
- Repdigit numbers that are divisible by 7.at n=25A366596