186623

Appears in sequences

• Numbers that are the product of a pair of twin primes.at n=22A037074
• Product of twin primes of form (4*k+3,4*(k+1)+1), k>=0.at n=12A071700
• Squarefree numbers k such that A076341(k) = 0.at n=30A076352
• Numbers k such that k+1 and sigma(k)+1 are both perfect squares.at n=28A089954
• Numbers that are one less than a square and have exactly 4 divisors.at n=23A134020
• Members of A159053 which are not multiples of 3.at n=12A159054
• Numbers of the form i*6^j-1 (i=1..5, j >= 0).at n=33A181288
• Semiprimes which are sub-perfect powers.at n=33A189045
• a(n) = 4*6^n-1.at n=6A198797
• Numbers k that form a primitive Pythagorean triple with k' and sqrt(k^2 + k'^2), where k' is the arithmetic derivative of k.at n=25A210503
• G-Lehmer numbers: Composite numbers k such that A060968(k) divides A201629(k).at n=17A235864
• Number of compositions of n in which the maximal multiplicity of parts equals 5.at n=16A243122
• Numbers n which are neither a prime nor a square of a prime such that there is no d, 2<=d<=n/2, which divides binomial(n-d-1,d-1) and is not coprime to n.at n=31A269135
• Composite numbers k such that 2^k == 1 (mod cototient(k)).at n=17A291619
• Numbers k such that k and k+1 are both nonprime-powers whose all distinct prime divisors are consecutive primes (A066312).at n=18A346910
• Numbers k such that k^2 + sopfr(k)^2 is a square, where sopfr = A001414.at n=25A386991