31679

Appears in sequences

• a(n) = prime(n) * prime(prime(n)).at n=21A073065
• a(n) is the smallest k such that number of non-unitary prime divisors of central binomial coefficient, A001405(k) = C(k, floor(k/2)) equals n.at n=24A081394
• a(n) = n^3 - (n+1)^2.at n=32A153257
• Positions in A181391 where the terms listed in A171863 appear.at n=25A171864
• Smallest number m such that A226460(m) = n.at n=23A226462
• Values of x such that x^2 + y^2 = 17^n with x and y coprime and 0 < x < y.at n=7A230622
• Numbers for which the root mean square of nontrivial divisors is an integer and which are not a square of prime numbers.at n=39A247137
• a(0)=1; a(1)=1; for n >= 2, a(n) = a(n-1) + a(n-A000005(n)).at n=29A320357
• Number of quadrilateral regions in a "frame" of size n X n (see Comments in A331776 for definition), divided by 8.at n=28A332596