319488

Appears in sequences

• a(n) = binomial(n,2) * 2^(n-1).at n=13A001815
• 15-almost primes (generalization of semiprimes).at n=21A069276
• Smallest Smith number with n prime factors.at n=13A104168
• Highly decomposable Smith numbers. A Smith number which sets a record for the number of prime factors (counting multiplicity) starting from first Smith number is called a highly decomposable Smith number.at n=9A104169
• a(n) = (n/4)*2^(n/2)*((1+sqrt(2))^2 + (-1)^n*(1-sqrt(2))^2).at n=26A187272
• G.f.: A(x) = 1 + x*B(x), where B(x) = 1 + x^2*C(x)^2, C(x) = 1 + x^3*D(x)^3, D(x) = 1 + x^4*E(x)^4, ...at n=44A228866
• Number of (n+1) X (4+1) 0..7 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 8 (constant-stress 1 X 1 tilings).at n=4A234734
• Number of (n+1) X (5+1) 0..7 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 8 (constant-stress 1 X 1 tilings).at n=3A234735
• T(n,k) is the number of (n+1) X (k+1) 0..7 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 8 (constant-stress 1 X 1 tilings).at n=31A234738
• T(n,k) is the number of (n+1) X (k+1) 0..7 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 8 (constant-stress 1 X 1 tilings).at n=32A234738
• The pi-based arithmetic derivative of the double factorial of n.at n=12A259409
• a(n) = phi(A291789(n)).at n=28A291805
• a(n) is the number of subsets of {1,2,...,n} that contain exactly two odd numbers.at n=24A330592
• a(n) is the least positive integer such that 2^n + a(n)*n*(n+1) equals a power of 2.at n=13A350329
• Sum of the number of cells alive after 2 generations of Conway's game of life for initial 1 X n cells taken in all 2^n combinations of alive or dead.at n=15A384694