-309

Appears in sequences

• a(n) = floor(Sum_{k=0..n} tan(k)).at n=33A051508
• a(n) = round(Sum_{k=0..n} tan(k)).at n=33A051509
• a(n) = round(Sum_{k=0..n} tan(k)).at n=35A051509
• a(n) = ceiling(Sum_{k=0..n} tan(k)).at n=34A051510
• a(n) = ceiling(Sum_{k=0..n} tan(k)).at n=35A051510
• Series expansion of (-3 - 2*x)/(1 + x - x^3) in powers of x.at n=36A078712
• Polynomial expansion sequence : p(x)=1 + x - x^5 + x^9 + x^10.at n=48A143605
• Triangle of characteristic polynomials, see Mathematica code.at n=32A158389
• L.g.f.: log( Sum_{n>=0} x^(n^2) ), the log of the characteristic function of the squares.at n=21A162552
• Triangle, read by rows, T(n,k,q) = c(k,q) + c(n-k,q) - c(n, q) where c(n,q) = Product_{j=1..n-1} ((q^(j+1) - 1)/(q-1)) and q = 2.at n=12A172091
• Expansion of f(x, x^7) / f(x, x^3) in powers of x where f(, ) is Ramanujan's general theta function.at n=49A259774
• Expansion of f(-x^6)^3 / (f(x)^2 * psi(x)) in powers of x where psi(), f() are Ramanujan theta functions.at n=7A262156
• First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 115", based on the 5-celled von Neumann neighborhood.at n=9A270184
• First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 123", based on the 5-celled von Neumann neighborhood.at n=9A270213
• First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 133", based on the 5-celled von Neumann neighborhood.at n=11A270235
• First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 331", based on the 5-celled von Neumann neighborhood.at n=9A271280
• First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 541", based on the 5-celled von Neumann neighborhood.at n=42A272808
• a(n) = A033879(A276086(n)).at n=17A324654
• Triangle read by rows: T(n,k) = (-1)^(n+1) * A000166(n) + (-1)^(k) * A000166(k) for n >= 2 and 1 <= k <= n-1.at n=14A373966
• Expansion of 1 / Sum_{k in Z} x^(2*k) / (1 - x^(5*k+2)).at n=34A375061