19602

Appears in sequences

• Coordination sequence for C_3 lattice: a(n) = 16*n^2 + 2 (n>0), a(0)=1.at n=35A010006
• a(0) = 1, a(n) = 25*n^2 + 2 for n > 0.at n=28A010015
• a(n) = 3^n - n^2.at n=9A024025
• Schoenheim bound L_1(n,n-4,n-5).at n=34A036830
• Row 3 of A007754.at n=25A058794
• Numbers n such that n*phi(n-1) is a perfect square.at n=19A069069
• Least number x such that gcd(phi(x), sigma(x)) = n.at n=32A073815
• Number of strings over Z_3 of length n with trace 0 and subtrace 1.at n=10A073948
• Number of strings over Z_3 of length n with trace 0 and subtrace 2.at n=10A073949
• Number of strings over Z_3 of length n with trace 1 and subtrace 0.at n=10A073950
• Number of strings over Z_3 of length n with trace 1 and subtrace 2.at n=10A073952
• Number of elements of GF(3^n) with trace 0 and subtrace 1.at n=10A074001
• Number of elements of GF(3^n) with trace 0 and subtrace 2.at n=10A074002
• Number of elements of GF(3^n) with trace 1 and subtrace 0.at n=10A074003
• Number of elements of GF(3^n) with trace 1 and subtrace 2.at n=10A074005
• a(n) is the least number k that A074389(k) = n.at n=32A074390
• Smallest number m such that GCD(a+b,a-b) = n, where a = sigma(m) and b = phi(m).at n=32A077102
• Least x=a(n) such that product of common prime-divisors [without multiplicity] of sigma(x) and phi(x) equals n; or 0 if n is not a squarefree number or if no such x exists. Among indices n only squarefree numbers arise because multiplicity of prime factors is ignored.at n=32A082057
• a(n) = 5*a(n-1)+a(n-2) for n>1, a(0)=2, a(1)=5.at n=6A087130
• Numbers k for which the quotient q(k)=(k+rev(k))/abs(k-rev(k)) is an integer.at n=13A087993