493697

Appears in sequences

• Pseudoquadprimes: p+4 for primes p where p+4 divides p^(p+4) + 4 and p+4 is composite.at n=31A100875
• Numbers in A191311 but not in A129521.at n=21A191592
• Odd non-Carmichael numbers with increasing numbers of bases to which they are pseudoprimes.at n=36A194946
• Pseudoprimes divisible by a smaller pseudoprime.at n=28A215150
• Fermat pseudoprimes to base 2 with three prime factors divisible by a smaller Fermat pseudoprime to base 2.at n=11A215944
• Pseudoprimes congruent to 7 mod 10.at n=20A317972
• Positive integers k such that (k+1)^4 has a divisor congruent to -1 modulo k.at n=59A350916
• a(0) = 1, a(1) = 2, and a(n) = 23*a(n-1) - a(n-2) - 4 for n >= 2.at n=5A350917
• a(n) is the smallest n-gonal number that is a Fermat pseudoprime to base 2 (A001567), or -1 if no such number exists.at n=14A371759