72899

Appears in sequences

• Numbers that are the product of a pair of twin primes.at n=17A037074
• a(n) = A065824(A047845(n+1)).at n=34A065884
• Product of twin primes of form (4*k+1,4*k+3), k>0.at n=8A071697
• a(n) = prime(2*n-1)*prime(2*n).at n=28A089581
• Numbers n such that n+1 and phi(n)+1 are both perfect squares.at n=34A089952
• Numbers k such that k+1 and sigma(k)+1 are both perfect squares.at n=21A089954
• Numbers that are one less than a square and have exactly 4 divisors.at n=18A134020
• Semiprimes which are sub-perfect powers.at n=27A189045
• Numbers k that form a primitive Pythagorean triple with k' and sqrt(k^2 + k'^2), where k' is the arithmetic derivative of k.at n=20A210503
• Increasing a(n)is the smallest number of the form p^a*q^b, where a,b are positive integers and p < q are odd primes such that max( p^a, q^b)/min( p^a, q^b) <= 1 + 2/prime(n).at n=30A229108
• Number of (n+1) X (5+1) 0..1 arrays with no 2 X 2 subblock having the sum of its diagonal elements greater than the maximum of its antidiagonal elements.at n=15A251125
• Number of (n+2)X(1+2) 0..3 arrays with every 3X3 subblock row and column sum equal to 0 3 5 6 or 8 and every 3X3 diagonal and antidiagonal sum not equal to 0 3 5 6 or 8.at n=6A252327
• Number of (n+2)X(7+2) 0..3 arrays with every 3X3 subblock row and column sum equal to 0 3 5 6 or 8 and every 3X3 diagonal and antidiagonal sum not equal to 0 3 5 6 or 8.at n=0A252333
• T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and column sum equal to 0 3 5 6 or 8 and every 3X3 diagonal and antidiagonal sum not equal to 0 3 5 6 or 8.at n=21A252334
• T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and column sum equal to 0 3 5 6 or 8 and every 3X3 diagonal and antidiagonal sum not equal to 0 3 5 6 or 8.at n=27A252334
• Records in A166133.at n=17A256403
• Consider numbers n such that A166133(n) sets a new record and also satisfies A166133(n)=A166133(n-1)^2-1; sequence gives values of A166133(n).at n=2A256423
• Semiprimes whose prime factors are of equal binary length and which differ from each other in one bit position only.at n=33A261073
• Semiprimes p*q for which p and q are successive primes and their binary representations differ from each other in one bit position only.at n=15A261080
• Numbers n which are neither a prime nor a square of a prime such that there is no d, 2<=d<=n/2, which divides binomial(n-d-1,d-1) and is not coprime to n.at n=26A269135