90121

Properties

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 54.at n=7A031642
• Primes with 23 as smallest positive primitive root.at n=24A061335
• a(n) = the numerator of the continued fraction [[n/1];[n/2],[n/3],..,[n/n]] = the numerator of [[n/n];[n/(n-1)],[n/(n-2)],..,[n/1]], where [x] is floor(x).at n=11A128599
• Emirps with a single 2 as the only prime digit.at n=32A179033
• Primes of the form 16n^2 + 121.at n=19A202083
• Smallest m such that the period of the continued fraction of sqrt(m) is A215485(n); records of A013646.at n=33A215508
• Primes of the form: concatenation n with n-th composite integer.at n=6A246801
• Balanced primes of order thirteen.at n=22A300364
• Primes that are the first in a run of exactly 4 emirps.at n=28A346024
• Prime numbersat n=8728