21573

Appears in sequences

• Numbers n such that 69*2^n-1 is prime.at n=46A050560
• Number of unrooted Eulerian maps with bicolored faces which are self-isomorphic under reversing the colors.at n=13A090375
• a(n) = (2*n^3 + 5*n^2 + 5*n)/2.at n=26A162267
• Numbers k such that Sum_{i=1..k} i^6 divides Product_{i=1..k} i^6.at n=18A166606
• Numbers x such that the sum of all their cyclic permutations is equal to that of all cyclic permutations of sigma(x) and all cyclic permutations of Euler totient function phi(x).at n=21A247317
• Decimal representation of the x-axis, from the origin to the right edge, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 870", based on the 5-celled von Neumann neighborhood.at n=14A284306
• Expansion of Product_{i>0, j>0, k>0} 1/(1 - x^(i^2 + j^2 + k^2)).at n=53A321433
• Numbers that are the sum of eight fourth powers in exactly eight ways.at n=34A345840
• Array read by downward antidiagonals: A(n,k) = A(n-1,k+2) + Sum_{j=0..k} binomial(k,j)*A(n-1,j) with A(0,k) = 1, n >= 0, k >= 0.at n=40A369595
• Table in which the g.f. of row n, R(n,x), satisfies Sum_{k=-oo..+oo} (-1)^k * (x^k + n*R(n,x))^k = 1 + (n+2)*Sum_{k>=1} (-1)^k * x^(k^2), for n >= 1, as read by antidiagonals.at n=52A370020
• Expansion of g.f. A(x) satisfying Sum_{n=-oo..+oo} (-1)^n * (x^n + 3*A(x))^n = 1 + 5*Sum_{n>=1} (-1)^n * x^(n^2).at n=7A370023
• G.f. A(x) satisfies -3*x = Product_{n>=1} (1 - x^n/A(x)) * (1 - x^(n-1)*A(x)) * (1 + x^n).at n=9A384273