4194303

Appears in sequences

• a(n) = 2^n - 1. (Sometimes called Mersenne numbers, although that name is usually reserved for A001348.)at n=22A000225
• Number of 2n-bead balanced binary necklaces of fundamental period 2n, equivalent to reversed complement; also Dirichlet convolution of b_n=2^(n-1) with mu(n); also number of components of Mandelbrot set corresponding to Julia sets with an attractive n-cycle.at n=22A000740
• Divisors of 2^22 - 1.at n=15A003531
• Stirling numbers of second kind S2(23,n).at n=1A011572
• Number of Barlow packings with group P63/mmc(S) that repeat after 4n layers.at n=22A011946
• Nexus numbers (n+1)^22 - n^22.at n=1A022538
• a(n) = 4^n - 1.at n=11A024036
• a(n) = period of x^n + x + 1 over GF(2), i.e., the smallest integer m>0 such that x^n + x + 1 divides x^m + 1 over GF(2).at n=21A046932
• Numbers that are repdigits in base 4.at n=33A048329
• a(n) = Sum_{1<=k<=n, gcd(k,n)=1} 2^(k-1).at n=22A054432
• Difference between 2^n and largest square strictly less than 2^n.at n=42A056007
• Number of primitive (aperiodic) word structures of length n which contain exactly two different symbols.at n=22A056278
• Number of periodic palindromic structures of length n using exactly two different symbols.at n=44A056508
• Numbers that are both lucky numbers (A000959) and of form 2^k-1 (A000225).at n=14A057613
• Nim-factorial(a(n))=1.at n=26A060152
• a(n) = 2^n + (-1)^(n+1).at n=22A062510
• a(n) = 2^n - mu(n).at n=21A062777
• Biased numbers: n such that all terms of the sequence f(n), f(f(n)), f(f(f(n))), ..., 1, where f(k) = floor(k/2), are odd.at n=41A066880
• Squarefree part of 2^n-1 : the smallest number such that a(n)*(2^n-1) is a square.at n=21A069112
• a(0) = 1; a(n) = a(n-1)+1 if n is even, otherwise a(n) = 2*a(n-1).at n=42A075427