27243

Appears in sequences

• Numbers k such that 7*4^k + 1 is prime.at n=26A002255
• a(n) is the concatenation of n and 9n.at n=26A009474
• Number of n X n symmetric binary matrices with each 1 adjacent to no more than 5 knight-move neighboring 1s.at n=4A191573
• Number of permutations of [n] having exactly 6 strong fixed blocks.at n=4A225967
• Difference between the number of primes with n digits (A006879) and the nearest integer to F[4n](S(n)), where F[4n](x) are Fibonacci polynomials and S(n) = Sum_{i=0..3} (C(i)*(log(log(A*(B+n^2))))^i) (see A228063).at n=7A228064