Number of permutations p of 1,2,...,n such that both numerator and denominator of the continued fraction [p(1); p(2),...,p(n)] are primes.

A078431

Number of permutations p of 1,2,...,n such that both numerator and denominator of the continued fraction [p(1); p(2),...,p(n)] are primes.

Terms

    a(0) =0a(1) =1a(2) =1a(3) =3a(4) =3a(5) =20a(6) =126a(7) =694a(8) =2874a(9) =25059a(10) =218517a(11) =2054986a(12) =21050226

External references