31827

Appears in sequences

• Composite numbers k+1 such that k*phi(k+1) is a perfect square.at n=27A069068
• 3p^2 where p runs through the primes.at n=26A079705
• Numbers of the form 20*k+7 which are three times a square.at n=20A192328
• 3*h^2, where h is an odd integer not divisible by 3.at n=34A229852
• A recurrence relation conditioned on the primality of the preceding terms.at n=41A236768
• Number of sets of nonempty subsets of {1,...,n} with intersection {}.at n=4A318129
• Number of multiples of n which have only distinct and nonzero digits in base 10.at n=31A328287
• a(n) is the smallest dividend m of the Euclidean division m = d*n + r such that m/d = r/n.at n=28A335717
• Numbers that can be represented in more than one way as p^2+p*q+q^2 with p and q primes, p<=q.at n=27A349987
• Numbers of the form p^2*q, with odd primes p > q, such that q divides p-1.at n=19A350638