7777777777

Appears in sequences

• a(n) = 7*(10^n - 1)/9.at n=10A002281
• a(n)*n = A112904(n).at n=9A112905
• Let s(n) be the smallest number x such that the decimal representation of n appears as a substring of the decimal representations of the numbers [0...x] more than x times.at n=6A164321
• a(n) is the smallest number x such that the decimal representation of n appears as a substring of the decimal representations of the numbers [1...x] >= x times.at n=7A164935
• Numbers n such that the decimal digits of n are not present in k*n, k=2..9.at n=29A175637
• Repdigit numbers n such that the repeated digit of n is equal to the digital root of n.at n=28A271569
• a(n) = smallest positive number k with all digits equal such that the concatenation k||n||k is prime, or -1 if no such k exists.at n=26A338366
• Numbers with all digits equal and from the set {1, 3, 7, 9}.at n=38A338712
• Repdigit numbers that are divisible by 7.at n=18A366596
• Happy repdigit numbers.at n=11A381046