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A296199
Numerator of the contraharmonic mean of the first n primes.
1
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
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
KEYWORD
nonn,frac
AUTHOR
Andres Cicuttin, Dec 07 2017
STATUS
approved