18168

Appears in sequences

• Roman numerals for n evaluated as if in Sallows' base 27.at n=29A073427
• Composite Fibonacci sequence: each term is the composite with index equal to the sum of the previous two terms.at n=13A107390
• A good sequence of gaps for Shellsort, found by genetic programming.at n=10A112263
• Numbers k such that k + sigma(k) + phi(k) is a square.at n=26A116009
• a(n) = 13*n^2 + 10*n + 1.at n=37A161587
• Expansion of c(x/(1-x-x^2)) / (1-x-x^2), c(x) the g.f. of A000108.at n=8A184018
• Number of 6 X (n+1) 0..1 arrays with every 2 X 2 subblock having the same number of equal edges as its horizontal neighbors and a different number from its vertical neighbors, and new values 0..1 introduced in row major order.at n=6A208087
• Number of (n+2) X (1+2) 0..3 arrays with every 3 X 3 subblock row, column, diagonal and antidiagonal sum not equal to 0 3 4 6 or 7.at n=8A252132
• T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row, column, diagonal and antidiagonal sum not equal to 0 3 4 6 or 7.at n=36A252139
• Consider Post's tag system applied to the word (100)^n; a(n) = position of the longest word in the orbit, or -1 if the orbit is unbounded.at n=13A291796
• G.f.: exp( Sum_{n>=1} A322191(n)*x^n/n ), where A322191(n) is the coefficient of x^n*y^n/n in log( Product_{n>=1} 1/(1 - (x^(2*n) - y^(2*n))/(x - y)) ).at n=10A322192
• Number of essentially parallel unoriented series-parallel networks with n elements and without multiple unit elements in parallel.at n=12A339295
• Expansion of Sum_{k>=0} (x * (1 + k*x^2))^k.at n=13A360748
• a(n) = (1/(5*n+3)) * Sum_{k=0..n} (5*k+3) * binomial(5*n+3,n-k).at n=5A390779