Sequences

Inverse of 2002nd cyclotomic polynomial.

a(n) = (tau(n^n)+n-1)/n.

Probably an erroneous version of A016017.

Least k such that 2*n*k + 1 is a prime.

Inverse of 2006th cyclotomic polynomial.

Number of iterations of Reverse and Add which lead to a palindrome, or -1 if no palindrome is ever reached.

Smallest k such that 1/k can be written as a sum of exactly 2 unit fractions in n ways.

Least k such that (tau(k^3)+2)/3=n.

Inverse of 2010th cyclotomic polynomial.

Least k such that (tau(k^4)+3)/4=n.

Number of permutations of {1,2,...,n} in which each element follows its proper divisors.

Inverse of 2013th cyclotomic polynomial.

Inverse of 2014th cyclotomic polynomial.

Inverse of 2015th cyclotomic polynomial.

Least k such that (tau(k^k)+k-1)/k=n.

Smallest base relative to which n is palindromic.

Indices of prime Mersenne numbers (A001348).

Expansion of (1 - x + x^4) / (1 - x)^3.

a(1) = a(2) = 1, a(2n + 1) = 2*a(2n) and a(2n) = 2*a(2n - 1) + (-1)^n.

Inverse of 2021st cyclotomic polynomial.

De Bruijn's sequence: 2^(2^(n-1) - n): number of ways of arranging 2^n bits in circle so all 2^n consecutive strings of length n are distinct.

Least positive integer that is the sum of two squares of positive integers in exactly n ways.

Inverse of 2024th cyclotomic polynomial.

Numbers having n self generators (not necessarily primitive).

a(n) = Sum_{j|n, 1 < j < n} phi(j). Also a(n) = n - phi(n) - 1 for n > 1.

Row sums of triangle A000369.

Map numbers to number of letters in English name; sequence gives number of steps to converge (to 4).

Strictly non-palindromic numbers: n is not palindromic in any base b with 2 <= b <= n-2.

Inverse of 2030th cyclotomic polynomial.

Integer part of Chebyshev's theta function: floor( log(Product_{k=1..n} prime(k)) ).

Primes that are palindromic in base 2 (but written here in base 10).

Inverse of 2033rd cyclotomic polynomial.

2^(2^n) +- 1 without repeats.

Inverse of 2035th cyclotomic polynomial.

a(n) is the smallest prime p(k) such that the gaps between the primes p(k), p(k+1), p(k+2), ..., p(k+n) are 2, 4, 6, ... 2n.

First occurrence of exactly n identical terms in A007448.

Smallest prime factor of Mersenne numbers 2^p-1, where p is prime.

Least k such that (2*p_n)*k + 1 | Mersenne(p_n), p_n = n-th prime, n >= 2.

Inverse of 2040th cyclotomic polynomial.

Inverse of 2041st cyclotomic polynomial.

Numbers of the form 9*k+3 or 9*k+6.

a(1) = 3; for n >= 1, a(n+1) = a(n) + sum of its digits.

Inverse of 2044th cyclotomic polynomial.

Numbers n such that (13^n - 1)/12 is prime.

Inverse of 2046th cyclotomic polynomial.

Inverse of 2047th cyclotomic polynomial.

Pseudo-powers to base 3: numbers k that are not powers of 3 such that k divides 2^k + 1.

Primitive pseudo-powers to base 3.

(s(n)+s(n+1))/6, where s()=A006521.

(s(n)+s(n+1))/18, where s()=A006521.