25053

Appears in sequences

• Numbers k such that 2*10^k + 5*R_k + 2 is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=16A099006
• Indices of primes in sequence defined by A(0) = 41, A(n) = 10*A(n-1) + 81 for n > 0.at n=16A101738
• Number of branches in all hex trees with n edges (n>=1).at n=6A126180
• Numbers such that the digital sums in bases 2, 3, 5 and 7 all are equal.at n=29A135127
• Triangle of coefficients of characteristic polynomials of anti-symmetrical tridiagonal matrices: Middle diagonal: a=1; Lower first subdiagonal: b=2; Upper first subdiagonal: c=-2; Example: M(3) {{1, -2, 0}, {2, 1, -2}, {0, 2, 1}}.at n=57A136643
• Numbers n such that n^6 + 272 is prime.at n=35A161998
• Sum of the largest parts of the partitions of n into 9 squarefree parts.at n=47A326532
• Numbers k such that k![4] - 128 is prime, where k![4] = A007662(k) = quadruple factorial.at n=39A329176