OFFSET
2,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 2..1000
EXAMPLE
a(2) = 19 because 19 = (5*7 + 3)/2;
a(3) = 41 because 41 = (7*11 + 5)/2;
a(4) = 83 because 73 = (11*13 + 3)/2.
MATHEMATICA
f[n_] := Block[{k = 2, q = Prime[n]Prime[n + 1]}, While[p = Prime[k]; !PrimeQ[(q + p)/2], k++ ]; (q + p)/2]; Table[ f[n], {n, 2, 44}] (* Robert G. Wilson v, Nov 29 2004 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Giovanni Teofilatto, Nov 28 2004
EXTENSIONS
Edited, corrected and extended by Robert G. Wilson v, Nov 29 2004
STATUS
approved