326040

Appears in sequences

• Numbers k such that k+1 and 3*k+1 are perfect squares.at n=5A045899
• For n > 5, a(n) = 15*a(n-1) - 15*a(n-2) + a(n-3); initial terms are 1, 3, 8, 120, 1680.at n=6A051047
• a(n) = 3*a(n-1) + 3*a(n-2) - a(n-3); a(0) = 1, a(1) = 0, a(2) = 3. a(n) = 4*{a(n-1)+(-1)^n}-a(n-2); a(0) = 1, a(1) = 0.at n=11A120892
• Smallest octagonal number with n distinct prime factors.at n=5A156239
• Numbers with prime factorization p*q*r*s*t*u^3 (where p, q, r, s, t, u are distinct primes).at n=13A190378
• Denominators a(n) of Pythagorean approximations b(n)/a(n) to sqrt(3).at n=9A195499
• Numbers n such that the multiplicative group modulo n is the direct product of 7 cyclic groups.at n=14A272597
• a(n) is the smallest n-gonal number divisible by exactly n n-gonal numbers.at n=5A358859
• Numbers of the form (p+1)*(p+3) where (p,p+2) is a twin prime pair (cf. A001359).at n=25A362941