OFFSET
2,2
COMMENTS
Trying to translate the Goldbach conjecture into multiplication.
LINKS
Isaac E. Lambert and Charles R Greathouse IV, Table of n, a(n) for n = 2..10000 (first 100 terms from Lambert)
EXAMPLE
For example, the 13th term of the sequence is 43 since 26 = 3 + 23 (and the product 69 is minimal) and 3*23 - 26 = 43.
MATHEMATICA
f[n_] := Block[{p = 2}, While[ !PrimeQ[ 2n - p], p = NextPrime@ p]; 2n(p - 1) - p^2]; Array[f, 59, 2] (* Robert G. Wilson v, Mar 25 2012 *)
PROG
(PARI) a(n)=n+=n; forprime(p=2, default(primelimit), if(isprime(n-p), return(p*n-p^2-n))) \\ Charles R Greathouse IV, Mar 26 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Isaac Lambert, Apr 23 2008
EXTENSIONS
Edited by N. J. A. Sloane, May 23 2008
STATUS
approved