A296199 Numerator of the contraharmonic mean of the first n primes.

2, 13, 19, 87, 52, 377, 333, 1027, 389, 799, 1679, 4727, 3204, 8257, 5233, 4425, 4189, 20477, 12483, 30007, 4417, 41577, 24233, 56387, 16449, 75997, 43303, 32685, 13742, 122705, 69417, 155995, 43691, 64695, 108143, 239087, 32967, 290305, 159097, 116041

Offset

1,1

Links

Table of n, a(n) for n=1..40.

Wikipedia, Contraharmonic mean.

Formula

a(n) = numerator( Sum_{k=1..n} prime(k)^2/Sum_{k=1..n} prime(k) ).

a(n) = numerator( A024450(n)/A007504(n) ).

Mathematica

a[n_]:=ContraharmonicMean[Prime[Range[n]]];
nmax=40;
at=Table[a[n], {n, 1, nmax}];
Numerator[at]

Crossrefs

Cf. A007504 (sum of the first n primes), A024450 (sum of squares of the first n primes), A294612 (denominators).

Sequence in context: A027705 A296938 A350976 * A121181 A007355 A339611

Adjacent sequences: A296196 A296197 A296198 * A296200 A296201 A296202

Keyword

nonn,frac

Author

Andres Cicuttin, Dec 07 2017

Status

approved