51983

Appears in sequences

• Numbers that are the product of a pair of twin primes.at n=15A037074
• n-th 6k+1 prime times n-th 6k-1 prime.at n=23A048629
• Composite numbers k that divide Fibonacci(k+1).at n=20A069107
• Product of twin primes of form (4*k+3,4*(k+1)+1), k>=0.at n=7A071700
• Multiplicative closure of twin prime pair products (A037074).at n=34A074480
• Squarefree numbers k such that A076341(k) = 0.at n=16A076352
• Odd Fibonacci pseudoprimes: odd composite numbers k such that either (1) k divides Fibonacci(k-1) if k == +-1 (mod 5) or (2) k divides Fibonacci(k+1) if k == +-2 (mod 5).at n=29A081264
• Sum of n-th antidiagonal of array in A082002.at n=36A082005
• a(n) = prime(2*n-1)*prime(2*n).at n=24A089581
• Numbers n such that n+1 and phi(n)+1 are both perfect squares.at n=30A089952
• Numbers k such that k+1 and sigma(k)+1 are both perfect squares.at n=19A089954
• Molien series for genus 2 complete weight enumerators of self-dual codes over GF(3).at n=13A092069
• Odd composites m that divide Fibonacci(m)-1.at n=20A094394
• Odd numbers k that divide Lucas(k) + 1.at n=20A094399
• Numbers k that divide both Fibonacci(k+1) and Lucas(k) + 1.at n=13A094402
• Odd numbers k that divide Fibonacci(k) - 1 but not Fibonacci(k-1).at n=13A094409
• Numbers k that divide Fibonacci(k+1) but do not divide Fibonacci(k) + 1.at n=18A094412
• Integer part of n#/(p-3)#, where p=preceding prime to n.at n=48A102790
• Numbers k which divide the sum of the Fibonacci numbers F(1) through F(k) and such that k is not a multiple of 24.at n=35A124456
• a(n) = pq + pr + qr with p = prime(n), q = prime(n+1), and r = prime(n+2).at n=30A127345