53098

Appears in sequences

• Numbers k such that sigma(phi(k)) = sigma(k) where sigma is the sum of divisors function A000203 and phi is the Euler totient function A000010.at n=15A033631
• Generating function = g(g(x)), where g(x) = g.f. of Jacobsthal numbers A001045.at n=10A301699
• Number of n X n 0..1 arrays with every element unequal to 0, 1, 3, 4 or 6 king-move adjacent elements, with upper left element zero.at n=6A304538
• Number of nX7 0..1 arrays with every element unequal to 0, 1, 3, 4 or 6 king-move adjacent elements, with upper left element zero.at n=6A304543
• a(n) is the determinant of the 2 X 2 matrix whose entries (when read by rows) are the n-th primes ending in 1, 3, 7, 9 respectively.at n=22A335592