26869

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 13.at n=21A031601
• Smallest number that can be made to take n steps to reach 0 under "k -> any product of 2 numbers whose concatenation is k".at n=23A035934
• Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 23.at n=22A051988
• a(0)=1; a(1)=1; a(2)=1; a(n) = a(n-1) + (1 + a(n-2))*(1 + a(n-3)).at n=9A063404
• Odd composites (including 1 in the count) where the number 1 mod 4 equals the number 3 mod 4.at n=5A093180
• a(n) is the smallest odd number that makes a(n)*2^N(n)-1 prime, where N(n) is the n-th Mersenne number that makes 2^N(n)-1 prime.at n=33A135434
• Composite numbers that divide at least one Euclid number.at n=5A297894