36894

Appears in sequences

• Poincaré series [or Poincare series] (or Molien series) for mod 2 cohomology of universal W-group W(3).at n=21A014696
• Number of primitive (period n) periodic palindromes using exactly three different symbols.at n=17A056499
• Number of humps in all Motzkin paths of length n. (A hump is an upstep followed by 0 or more flatsteps followed by a downstep.)at n=12A097861
• Expansion of 2/(sqrt(1-2*x-3*x^2)*(1+x+sqrt(1-2*x-3*x^2))).at n=11A113682
• Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in two by two blocks.at n=10A145864
• Number of binary strings of length n avoiding "squares" (that is, repeated blocks of the form xx) with |x| > 3.at n=16A230177
• Number of (2+1) X (n+1) 0..1 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=12A253436
• Expansion of Product_{k>=1} ((1 + k*x^k) / (1 - x^k)).at n=17A267004
• The number of tilings of an equilateral triangle of side length n with k lozenges and n^2 - 2*k unit triangles. Triangle T(n, k) with n >= 1 and 0 <= k <= n*(n + 1)/2, read by rows.at n=19A273464
• G.f. A(x) satisfies A(x) = 1 + x + x^4*A(x)^2.at n=33A366554
• Smallest k for which the number of divisors d of k such that d == -d^(k/d) (mod k) is equal to n, or -1 if no such k exists.at n=5A390392