655360

Appears in sequences

• Maximum m such that there are no two adjacent elements belonging to the same n-th power residue class modulo some prime p in the sequence 1,2,...,m (equivalently, there is no n-th power residue modulo p in the sequence 1/2,2/3,...,(m-1)/m).at n=15A000236
• Generalized class numbers c_(n,2).at n=15A000362
• a(n) = 10*4^n.at n=8A002066
• Triangle of coefficients in expansion of (4 + 5*x)^n.at n=37A013628
• Number of noninvertible 2 X 2 matrices over Z/nZ (determinant is a divisor of 0).at n=30A020479
• a(n) = 5 * 2^n.at n=17A020714
• Numbers of form 4^i*10^j, with i, j >= 0.at n=36A025621
• Expansion of (1 + 2x + 6x^2 + x^3)/(1 - 2x^2).at n=37A029745
• Triangle whose (i,j)-th entry is binomial(i,j)*4^(i-j)*8^j.at n=24A038238
• Triangle whose (i,j)-th entry is binomial(i,j)*8^(i-j)*4^j.at n=24A038282
• Number of 1's in all compositions of n+1.at n=17A045623
• Numbers n such that n+cototient(n) is a power of 2.at n=36A053159
• Nonprimes n such that n+cototient(n) is a power of 2.at n=29A053162
• a(n) = (9*2^n + (-2)^n)/4 for n>0.at n=17A056486
• Numbers k such that k = 2*phi(k) + phi(phi(k)).at n=32A063920
• Permutation of N induced by rotating the node 2 right in the infinite planar binary tree shown at A065658.at n=33A065662
• Products of exactly 18 primes (generalization of semiprimes).at n=3A069279
• Numbers of the form 5*2^n or 5*3*2^n; a(n) = 5*A029744(n).at n=33A070004
• Binary expansion is 1x100...0 where x = 0 or 1.at n=34A070875
• a(1)=2, a(n+1) = 2*a(n) - phi(a(n)) where phi is the Euler totient function A000010.at n=28A072944