1987021

Appears in sequences

• Strong pseudoprimes to bases 2 and 3.at n=2A072276
• Poulet numbers (2-pseudoprimes) of the form 7200*n^2 + 8820*n + 2701.at n=10A214016
• Composite numbers k congruent to 5 (mod 8) such that 2^((k-1)/2) mod k = k-1.at n=19A244626
• Record values in A265388.at n=37A265395
• Fermat pseudoprimes to base 2 that are triangular.at n=28A293622
• Fermat pseudoprimes to base 2 that are hexagonal.at n=27A322130
• Numbers that are super pseudoprimes to both bases 2 and 3.at n=19A333130
• Odd composite numbers k such that 2^((k-1)/2) == -1 (mod k).at n=28A356638
• Triangular numbers that are emirpimes.at n=30A375385