373319

Appears in sequences

• Composite numbers n such that the sum of divisors of n, sigma(n), divided by the number of divisors, d(n) and sigma(n) minus n are both rational squares.at n=18A049226
• a(n) = 4*n^4 + 8*n^3 - 4*n - 1 = (2*n^2 - 1)*(2*n^2 + 4*n + 1).at n=17A057769
• Expansion of (1+x+x^2)/((1-x^2)*(1-2*x-x^2)); a Pellian-related sequence.at n=14A114697
• Numbers n such that sum of divisors, sigma(n), and sum of the proper divisors, sigma(n)-n, are both square.at n=15A176996
• Numbers k such that 2 * A000217(k) + 1 is triangular.at n=15A216134
• Sequences A006452 and A216134 interlaced.at n=31A216162
• Nonprime terms in A210494.at n=38A230214
• a(n) = (2n-2)^3 + (2n-2) - 1.at n=36A255877