11609325domain: NAppears in sequencesa(0) = 1; a(n) = Sum_{k=1..n} (binomial(n,k) mod 2) * a(k-1) * a(n-k).at n=22A331519Smallest number having exactly n divisors of the form 8*k + 1.at n=32A343104Smallest number having exactly n divisors of the form 8*k + 5.at n=33A343106Odd numbers k such that A380845(k) > 2*k.at n=20A380932