OFFSET
1,1
EXAMPLE
a(5) = 3. The 5th prime is 11 and 2p is 22. The theorem says that there exists a number k, between p & 2p that is twice a square. 18 is between 11 & 22 and is of the form 2k^2, k being 3.
MATHEMATICA
Table[ Ceiling[ Sqrt[ Prime[ n ]/2 ] ], {n, 1, 100} ]
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Robert G. Wilson v, Jan 24 2002
STATUS
approved