19264

Appears in sequences

• Base-7 digits are, in order, the first n terms of the periodic sequence with initial period 1,1,0.at n=5A033134
• Sums of 4 distinct powers of 7.at n=11A038483
• Theta series of E_8 lattice with respect to midpoint of edge.at n=10A045819
• a(n) = (n+1)*binomial(2*n,n) - 2^(2*n-1).at n=6A065982
• Let u(1)=u(2)=1, u(3)=2n, u(k) = abs(u(k-1)-u(k-2)-u(k-3)) and M(k) = Max_{i<=i<=k} u(i), then for any k >= A078109(n), M(k) = floor(sqrt(k + a(n))).at n=21A078108
• Numbers n such that 3^n + 2^(n-1) is prime.at n=42A082103
• Number of Pythagorean quadruples mod n; i.e., number of solutions to w^2 + x^2 + y^2 = z^2 mod n.at n=27A096018
• Numbers k such that A111875(k) is prime and sets a new record for number of digits.at n=8A109320
• 7 times pentagonal numbers: a(n) = 7*n*(3*n-1)/2.at n=43A152744
• Molecular topological indices of the sun graphs.at n=15A192845
• Triangle T(n,k) read by rows: T(n,k) is the number of unrooted hypertrees on n labeled vertices with k hyperedges, n >= 2, 1 <= k <= n-1.at n=23A210587
• a(n) = 2^(n-1)*(3^n-2^(n+1)+1).at n=6A228701
• The number of P-positions in the game of Nim with up to 4 piles, allowing for piles of zero, such that the number of objects in each pile does not exceed n.at n=27A241522
• Composites whose prime factorization in base 3 is an anagram of the number in base 3.at n=35A260047
• Triangle T(n,r) read by rows: order of the semigroup of orientation-preserving partial transformations of n elements with breath r.at n=39A289710
• Practical numbers q with q + 2 and q^2 + 2 both practical.at n=12A294225
• Expansion of Product_{k>=1} (1 + x^k) * (1 + x^(2*k)) * (1 + x^(3*k)).at n=36A327045