3145726

Appears in sequences

• a(2*n) = 3*2^n - 2; a(2*n+1) = 2^(n+2) - 2.at n=40A027383
• a(n) = 3*2^n - 2.at n=20A033484
• a(n) = T(3,n), array T given by A047858.at n=18A047860
• Add 1, double, add 1, double, etc.at n=40A083416
• a(n) = B(2*n, 2)/B(2*n) (see formula section).at n=10A096045
• Duplicate of A033484.at n=20A099018
• Start with 1, then alternately double or add 2.at n=40A099942
• Expansion of x*(3*x^2+x+1)/((x-1)*(2*x-1)*(x+1)).at n=21A192033
• a(n) = 3*2^n - 2*(-1)^n.at n=20A259713
• a(0) = 1, a(n+1) = 2*a(n) + periodic sequence of length 2: repeat [5, -4].at n=20A280173
• 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 621", based on the 5-celled von Neumann neighborhood.at n=21A283357
• 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 637", based on the 5-celled von Neumann neighborhood.at n=21A283406
• Number of bisymmetric, quasitrivial, and order-preserving binary operations on the n-element set {1,...,n}.at n=21A296953
• a(n) = n! * [x^n] (2*x - 4*exp(x) + 3*exp(2*x) + 3) / 2.at n=21A369491