Sequences

Smallest nonempty set S containing prime divisors of 7k+6 for each k in S.

Smallest nonempty set S containing prime divisors of 7k+8 for each k in S.

Smallest nonempty set S containing prime divisors of 7k+9 for each k in S.

Smallest nonempty set S containing prime divisors of 7k+10 for each k in S.

Smallest nonempty set S containing prime divisors of 8k+1 for each k in S.

Smallest nonempty set S containing prime divisors of 8k+2 for each k in S.

Smallest nonempty set S containing prime divisors of 8k+3 for each k in S.

Smallest nonempty set S containing prime divisors of 8k+5 for each k in S.

Smallest nonempty set S containing prime divisors of 8k+6 for each k in S.

Smallest nonempty set S containing prime divisors of 8k+7 for each k in S.

Smallest nonempty set S containing prime divisors of 8k+9 for each k in S.

Smallest nonempty set S containing prime divisors of 8k+10 for each k in S.

Smallest nonempty set S containing prime divisors of 9k+1 for each k in S.

Smallest nonempty set S containing prime divisors of 9k+2 for each k in S.

Smallest nonempty set S containing prime divisors of 9k+3 for each k in S.

Smallest nonempty set S containing prime divisors of 9k+4 for each k in S.

Smallest nonempty set S containing prime divisors of 9k+5 for each k in S.

Smallest nonempty set S containing prime divisors of 9k+6 for each k in S.

Smallest nonempty set S containing prime divisors of 9k+7 for each k in S.

Smallest nonempty set S containing prime divisors of 9k+8 for each k in S.

Smallest nonempty set S containing prime divisors of 9k+10 for each k in S.

Smallest nonempty set S containing prime divisors of 10k+1 for each k in S.

Smallest nonempty set S containing prime divisors of 10k+3 for each k in S.

Smallest nonempty set S containing prime divisors of 10k+4 for each k in S.

Smallest nonempty set S containing prime divisors of 10k+7 for each k in S.

Smallest nonempty set S containing prime divisors of 10k+8 for each k in S.

Smallest nonempty set S containing prime divisors of 10k+9 for each k in S.

Least inverse of A001390, or 0 if no inverse exists.

Lpf(n): least prime dividing n (when n > 1); a(1) = 1. Or, smallest prime factor of n, or smallest prime divisor of n.

Successive record periods of continued fraction for sqrt(k) (period of continued fraction for sqrt(A013645(n+1))).

a(n)-th prime is sum of first k primes for some k.

n-th composite is sum of first k composites for some k.

a(n)-th squarefree is sum of first k squarefrees for some k.

a(n)-th nonsquarefree is sum of first k nonsquarefrees for some k.

Least positive integer k for which 4^n divides k!.

Least positive integer k for which 7^n divides k!.

Least positive integer k for which 8^n divides k!.

Least positive integer k for which 9^n divides k!.

Least quadratic nonresidue modulo n (with n >= 3).

Numerators in recursive bijection from positive integers to positive rationals (the bijection is f(1) = 1, f(2n) = f(n)+1, f(2n+1) = 1/(f(n)+1)).

Denominators in recursive bijection from positive integers to positive rationals (the bijection is f(1) = 1, f(2n) = f(n)+1, f(2n+1) = 1/(f(n)+1)).

Numerators in canonical bijection from positive integers to positive rationals.

Denominators in a certain bijection from positive integers to positive rationals.

Lexicographically earliest infinite increasing sequence of nonnegative numbers containing no 5-term arithmetic progression.

Lexicographically earliest increasing sequence of positive numbers that contains no arithmetic progression of length 5.

Lexicographically earliest increasing sequence of nonnegative numbers that contains no arithmetic progression of length 6.

Lexicographically earliest increasing sequence of nonnegative numbers that contains no arithmetic progression of length 7.

Lexicographically earliest increasing sequence of positive numbers that contains no arithmetic progression of length 7.

Lexicographically earliest increasing sequence of nonnegative numbers that contains no arithmetic progression of length 8.

Lexicographically earliest increasing sequence of positive numbers that contains no arithmetic progression of length 8.