23824

Appears in sequences

• Expansion of e.g.f. exp(x * cosh(x)).at n=9A003727
• Series for first parallel moment of square lattice.at n=14A006732
• Expansion of e.g.f. sin(x*cos(x)) (odd powers only).at n=4A009446
• Let c(k) denote the k-th composite number and p(k) the k-th prime number; then a(n) = Sum_{i=n*(n-1)/2+1 .. n*(n+1)/2} c(i) - Sum_{i=1..n} p(i).at n=34A024850
• a(n) = dot_product(n,n-1,...2,1)*(5,6,...,n,1,2,3,4).at n=43A026060
• a(n) = Sum_{k=1..n} -A068341(k+1)*a(n-k), a(0)=1.at n=15A073777
• Numbers k such that k^2 divides 15^k-1.at n=26A128395
• a(0)=3; a(n) = n^2 + a(n-1) for n>0.at n=41A153057
• Numbers k such that k^3 divides 15^(k^2) - 1.at n=43A177915
• Expansion of x*(1+2*x+8*x^2+4*x^3+3*x^4) / ( (1+x)^2*(x-1)^4 ).at n=31A178947
• a(1) = 31, a(n) = prime(a(n-1)) - 3a(n-1).at n=9A179514
• Number of -3..3 arrays x(i) of n+1 elements i=1..n+1 with set{t,u,v in 0,1}((x[i+t]+x[j+u]+x[k+v])*(-1)^(t+u+v)) having three, four, five, six, seven or eight distinct values for every i,j,k<=n.at n=4A211764
• a(3)=5, a(4)=8, a(5)=12; thereafter a(n) = a(n-1) + A000931(n+7).at n=27A220885
• 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 189", based on the 5-celled von Neumann neighborhood.at n=28A279718
• Numbers k such that k, k + 1 and k + 2 have the same number of divisors in Gaussian integers.at n=0A332313
• Number of smooth arithmetical structures on D_n.at n=38A335675
• Numbers k such that k and k+1 have the same sum of 5-smooth divisors.at n=15A355713
• a(n) = Sum_{k=1..n} k^3*sigma(k), where sigma is A000203.at n=8A364194
• Triangle read by rows: T(n,k) is the number of achiral combinatorial maps with n edges and genus k, 0 <= k <= floor(n/2).at n=22A380234