27585

Appears in sequences

• Number of noninvertible 2 X 2 matrices over Z/nZ (determinant is a divisor of 0).at n=13A020479
• Numbers k such that k and 3*k are anagrams.at n=14A023087
• Trajectory of 3 under map n->7n-1 if n odd, n->n/2 if n even.at n=40A063871
• E.g.f. satisfies: A'(x) = 1/(1 - x*A(x))^3 with A(0)=1.at n=6A238302
• Number of partitions p of n such that (number of numbers in p of form 3k) = (number of numbers in p of form 3k+1).at n=46A241744
• Expansion of f(x^3, x^9) * f(x^6, x^6) / f(-x, -x^2) in powers of x where f(,) is Ramanujan's general theta function.at n=33A257655
• Number of solutions to c(1)*prime(1)+...+c(2n)*prime(2n) = -1, where c(i) = +-1 for i > 1, c(1) = 1.at n=11A261061
• Number of black and white n-bead necklaces with at least 3 white beads (turning over is not allowed); also number of clockwise arrangements of reflex and non-reflex angles that can form an n-gon.at n=19A262232
• Number of 2 X 2 matrices with all elements in {-n,..,0,..,n} with determinant = 2*permanent.at n=28A280343
• Maximal coefficient of (1 + x^3) * (1 + x^5) * (1 + x^7) * ... * (1 + x^prime(n)).at n=24A369708