212421
domain: N
Appears in sequences
- Pseudoprimes k to base 2 such that k-2 and k+2 are primes.at n=2A057942
- Pseudoprimes (base-2) equal to product of 4 primes not necessarily distinct.at n=17A112441
- Sarrus numbers that become prime when two is added.at n=12A137198
- Pseudoprimes to a twin prime criterion of Aebi and Cairns.at n=13A224695
- Sarrus numbers (A001567) that are the average of two consecutive primes.at n=8A265684
- E.g.f. A(x) satisfies A(x) = 1/(exp(-x) - x*A(x)^2).at n=5A379886