19304

Appears in sequences

• a(n) = T(2n-1,n-1), where T is the array in A026120.at n=6A026127
• Partial sums of A000285.at n=17A053311
• n*10^6-1, n*10^6-3, n*10^6-7 and n*10^6-9 are all prime.at n=3A064980
• Indices of primes in sequence defined by A(0) = 19, A(n) = 10*A(n-1) - 21 for n > 0.at n=15A102025
• Even elements of A085493.at n=40A106431
• Numbers k such that k^3 contains a pandigital substring.at n=14A115933
• Number of open knight's tour diagrams of a 3 X n chessboard that are symmetric under 180-degree rotation and have "type B": the endpoints occur in different columns and disagree in color with the cells in the nearest corner.at n=18A169775
• Partial sums of tetranacci numbers (A000288).at n=16A189740
• Number of isomorphism classes of nanocones with 3 pentagons and a nearsymmetric boundary of length n.at n=37A198014
• Numbers which, when divided by the sum of their prime factors, give a prime number.at n=45A199013
• Row sums of the triangle in A208101.at n=15A208976
• Positions of 3's in A234323.at n=48A234804
• Numbers n such that phi(n)*sigma(n) = phi(n+1)*sigma(n+1).at n=12A244439
• Numbers k such that card({x|sigma(x)=k}) > 1 and (Sum_{sigma(x)=k} x) < k.at n=22A258931
• Numbers k such that (13*10^k + 437)/9 is prime.at n=20A282351
• a(n) = 3^n - 3*binomial(n,3) - 3*binomial(n,2) - 2*n - 1.at n=9A383343
• Numbers k such that k^2, (k+1)^2 and (k+2)^2 are all abundant numbers.at n=7A383391
• Number of integer partitions of n whose parts do not have choosable sets of strict integer partitions.at n=37A387137