49081

Properties

Appears in sequences

• Half-quartan primes: primes of the form p = (x^4 + y^4)/2.at n=19A002646
• Indices of prime repunits: numbers k such that 11...111 (with k 1's) = (10^k - 1)/9 is prime.at n=5A004023
• Expansion of 1/((1-2x)(1-9x)(1-10x)).at n=4A016321
• Triangle formed when cumulative boustrophedon transform is applied to 1, 0, 0, 0, ..., read by rows from left to right.at n=32A059431
• Triangle formed when cumulative boustrophedon transform is applied to 1, 0, 0, 0, ..., read by rows in natural order.at n=32A059432
• a(n+5) = (a(n+4)*a(n+1) + 2*a(n+3)*a(n+2))/a(n).at n=12A105236
• Primes that become squares when prefixed with a 5.at n=10A167738
• Numbers n such that (10^n-1)/9 is prime and can be written in the form a^2 + 3*b^2.at n=1A216529
• Primes p such that p+2, p+4, p+6, p+8, p+10 and p+12 are all semiprime.at n=3A241483
• Primes p such that p+2, p+4, p+6, p+8, p+10 are semiprimes.at n=11A241959
• Number of integers in n-th generation of tree T(3/4) defined in Comments.at n=53A274146
• A 3 X 3 magic square with five square entries, read by rows.at n=8A319589
• Prime numbersat n=5045