88457

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 20.at n=24A031608
• Numbers n such that n'' = n'+1 where n' and n'' are respectively the first and the second arithmetic derivative of n (A003415).at n=19A189639
• Numbers k such that 10^k - 401 is prime.at n=22A288821
• Numbers k for which sigma(k) = k + k'', where k'' is the second derivative of k (A068346).at n=20A348426
• a(n) = number of partitions of n whose difference multiset has at least one duplicate; see Comments.at n=45A364612