241001

Appears in sequences

• Brilliant Sarrus numbers.at n=20A086837
• Pseudoquadprimes: p+4 for primes p where p+4 divides p^(p+4) + 4 and p+4 is composite.at n=22A100875
• Pentagonal numbers (A000326) that are also brilliant numbers (A078972).at n=21A113941
• Semiprimes of the form n*(3*n-1)/2.at n=37A245365
• Semiprimes of the form (4*n + 1)*(6*n + 1) = 24*n^2 + 10*n + 1.at n=14A255584
• Irregular table read by rows: n-th row lists the 9 n-gonal numbers of a 3 X 3 semimagic square with the smallest magic sum. The terms of each row are arranged in the manner shown in A261816.at n=22A265141
• Fermat pseudoprimes to base 2 that are pentagonal.at n=1A293623
• Numbers k > 1 such that 2^k == 2 (mod k) and gcd(k, 3^k - 3) = 1.at n=7A300762
• Numbers k such that 2^(k-1) == 1 (mod k) and lpf(k)-1 does not divide k-1.at n=12A316906
• Numbers k such that 2^(k-1) == 1 (mod k) and p-1 does not divide k-1 for every prime p dividing k.at n=10A316907