393215

Appears in sequences

• a(0) = 1; a(n) = 3*2^n - 1, for n > 0.at n=17A052940
• a(2n) = 2*2^n - 1, a(2n+1) = 3*2^n - 1.at n=35A052955
• a(0) = 0; for n > 0, a(n) = 3*2^(n-1) - 1.at n=18A055010
• Smallest number x > 1 such that phi(x) + sigma(x) = k*d(x)^n, i.e., the left-hand side is divisible by the n-th power of the number of divisors.at n=8A055470
• Variation on Ulam numbers: a(1) = 1; a(2) = 2; for n>2, a(n) = smallest (n odd) or largest (n even) number > a(n-1) that is a unique sum of two distinct earlier terms.at n=35A081026
• a(0) = 1; for n > 0, a(n) = 3*2^(n-1) - 1.at n=18A083329
• Add 1, double, add 1, double, etc.at n=35A083416
• a(n) = 3*2^floor((n-1)/2) + (-1)^n.at n=34A097581
• Smallest semiprime with Hamming weight n (i.e., smallest semiprime with exactly n ones when written in binary), or -1 if no such number exists.at n=17A102029
• Slater-Velez permutation sequence of the 2nd kind.at n=34A129198
• a(n) = 6*4^n - 1.at n=8A140529
• a(n) = 3*(-1)^(n+1)*2^n - 1.at n=17A140683
• a(n) = 3*2^n - 1.at n=17A153893
• Numbers k such that A249441(k) = 3.at n=28A249452
• Decimal representation of the n-th iteration of the "Rule 155" elementary cellular automaton starting with a single ON (black) cell.at n=9A263245
• Numbers n such that the Shevelev polynomial {m, n} has a root at m = -1.at n=25A264613
• Independence number of the n-Mycielski graph.at n=19A266550
• Number of length-n 0..2 arrays with no following elements greater than or equal to the first repeated value.at n=15A267226
• Decimal representation of the x-axis, from the origin to the right edge, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 641", based on the 5-celled von Neumann neighborhood.at n=18A283507
• Decimal representation of the x-axis, from the left edge to the origin, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 873", based on the 5-celled von Neumann neighborhood.at n=19A284349