Let v = list of denominators of Farey series of order n (see A006843); let b(n) = Sum 1/(k+k'), where (k,k') are pairs of successive terms of v; a(n) = denominator of b(n).

A278051

Let v = list of denominators of Farey series of order n (see A006843); let b(n) = Sum 1/(k+k'), where (k,k') are pairs of successive terms of v; a(n) = denominator of b(n).

Terms

    a(0) =2a(1) =3a(2) =10a(3) =35a(4) =252a(5) =2772a(6) =6435a(7) =858a(8) =680680a(9) =12932920a(10) =5290740a(11) =121687020a(12) =1029659400a(13) =3088978200a(14) =582272390700a(16) =128701918800a(17) =25740383760

External references