1310720

Appears in sequences

• Expansion of (1+x)/(1-4*x).at n=10A003947
• a(n) = 5 * 2^n.at n=18A020714
• Numbers of form 5^i*8^j, with i, j >= 0.at n=37A025623
• Expansion of (1 + 2x + 6x^2 + x^3)/(1 - 2x^2).at n=39A029745
• Numbers n such that n+cototient(n) is a power of 2.at n=39A053159
• Nonprimes n such that n+cototient(n) is a power of 2.at n=32A053162
• Numbers k such that k = 2*phi(k) + phi(phi(k)).at n=34A063920
• Fourth column of triangle A067410.at n=7A067412
• Triangle with columns built from certain power sequences.at n=37A067425
• 19-almost primes (generalization of semiprimes).at n=3A069280
• Numbers of the form 5*2^n or 5*3*2^n; a(n) = 5*A029744(n).at n=35A070004
• Binary expansion is 1x100...0 where x = 0 or 1.at n=36A070875
• a(n) = n*2^(n-4).at n=16A079859
• Triangle of coefficients in expansion of sinh^2(n*x) in powers of sinh(x).at n=46A082649
• Expansion of g.f.: (1+x^2)/(1-2*x).at n=20A084215
• a(0)=1, a(1)=5, a(n+2)=4a(n), n>0.at n=19A084568
• a(0) = a(1) = 1; for n > 1, a(n) = (n+2)*2^(n-2).at n=18A087447
• a(n) = Sum_{k=0..n} binomial(n+(-1)^k, k).at n=19A087940
• Denominators of the Taylor series of arccosh(z)/sqrt(2(x-1)) about 1.at n=7A091019
• Numbers of the form 2^k or 5*2^k.at n=39A094958