30757

Properties

Appears in sequences

• Indices of prime Fibonacci numbers.at n=28A001605
• Numbers k such that the continued fraction for sqrt(k) has period 69.at n=30A020408
• a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (Fibonacci numbers), t = (primes).at n=25A024468
• a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (Fibonacci numbers), t = (primes).at n=24A025088
• Primes p from A031924 such that A052180(primepi(p)) = 19.at n=24A052235
• a(1) = 1; a(2n) is the smallest prime == 1 mod (a(2n-1)) and a(2n+1) is the smallest composite number == 1 (mod a(2n)).at n=21A075340
• a(1) = 1, a(2n) is the smallest composite number == 1 mod (a(2n-1)) and a(2n+1) is the smallest prime == 1 (mod a(2n)).at n=26A075341
• Prime indices of prime Fibonacci numbers.at n=27A083668
• Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 6 which is symmetric after a rotation by 180 degrees.at n=5A123795
• Primes of the form 2n^2 + 5.at n=36A201474
• Primes of the form 8n^2 + 5.at n=18A201612
• Numbers n such that the n-th Fibonacci number is prime, but cannot be written in the form a^2 + 7*b^2.at n=13A216536
• Numbers n such that the n-th Fibonacci number is prime, but cannot be written in the form a^2 + 3*b^2.at n=14A216553
• Numbers n such that the n-th Fibonacci number is prime and can be written in the form a^2 + 2*b^2.at n=14A216558
• Numbers n such that the n-th Fibonacci number is prime, but cannot be written in the form a^2 + 5*b^2.at n=15A216561
• Numbers n such that the n-th Fibonacci number is prime, but cannot be written in the form a^2 + 6*b^2.at n=21A216570
• Numbers n such that the n-th Fibonacci number is prime, but cannot be written in the form a^2 + 10*b^2.at n=22A216574
• Primes of the form 2*n^2 + 46*n + 21.at n=11A217495
• Primes abs(A337145(k))/8 for k in A337146.at n=6A337147
• Smallest number k with A355915(k) = n.at n=40A356792