22687

Appears in sequences

• Discriminants of quintic fields with 2 complex conjugates (negated).at n=41A023684
• Expansion of Sum_{p prime, i>=1} x^(p^i)/(1 - x^(p^i)) / Product_{p prime, j>=1} (1 - x^(p^j)).at n=41A281616
• Number of tilings of a 12 X n rectangle using 2*n copies of the disconnected shape [ooo___ooo].at n=25A323423
• Starts of runs of 4 consecutive Gray-code Niven numbers (A344341).at n=27A344344
• Starts of runs of 3 consecutive numbers that have an equal number of unitary and nonunitary prime divisors (A348097).at n=22A348099
• a(n) = Sum_{j=1..n} Sum_{k=1..n} phi(j*k) / phi(k).at n=38A372636