270271

Properties

Appears in sequences

• In the '3x+1' problem, these values for the starting value set new records for highest point of trajectory before reaching 1.at n=22A006884
• Primes formed by concatenating n with n+1.at n=31A030458
• Denominators of continued fraction convergents to sqrt(469).at n=10A041895
• Primes whose decimal expansion is a concatenation of two or more consecutive increasing numbers (no leading zeros allowed).at n=32A052087
• In the '3x+1' problem, these values for the starting value set new records for the "dropping time", number of steps to reach a lower value than the start.at n=7A060412
• a(1) = 1, then add, multiply, subtract, multiply 2, 3, 4, 5; 6, 7, 8, 9; ... in that order.at n=13A077384
• Numerator of Sum_{k=1..n} k^2*H_{n+k} where H_m = Sum_{i=1..m}.at n=6A102720
• Primes formed by concatenating k with k+1, where k+1 is a prime.at n=15A134428
• Primes of the form 2*k!! + 1.at n=10A215777
• Least m such that the Collatz (3x+1) iteration of m has exactly n increasing peak values.at n=36A221470
• In the '3x+1' problem, primes which as starting values set new records for number of steps to reach 1, where a step means either 'divide by two' or 'triple plus one and then divide by two'.at n=32A244638
• Primes p with p-1, p+1, prime(p)-1 and prime(p)+1 all practical.at n=33A257924
• Numbers k such that psi(phi(k))/k > psi(phi(m))/m for all m < k, where phi is Euler's totient function (A000010) and psi is the Dedekind psi function (A001615).at n=27A293712
• Primes that are the average of two consecutive primorial numbers A002110 plus one.at n=2A357517
• Prime numbersat n=23666