OFFSET
1,1
COMMENTS
A rational number is created by 1/n + 1/n^2 + 1/(n+1) + 1/(n+1)^2 and has a reduced numerator of 2*n^3 + 5*n^2 + 3*n + 1.
From n=1 to 100, 38 primes, 48 semiprimes, and 14 numbers requiring three or more prime factors were created. This is very anomalous compared to the expected distribution of such numbers from 1 to 2050301.
EXAMPLE
For n=37, 2*37^3 + 5*37^2 + 3*37 + 1 = 108263, a prime.
MATHEMATICA
Select[Table[2n^3+5n^2+3n+1, {n, 100}], PrimeQ] (* Harvey P. Dale, Jan 21 2014 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
J. M. Bergot, Sep 28 2011
EXTENSIONS
Entries corrected by R. J. Mathar, Sep 28 2011
STATUS
approved