OFFSET
1,1
FORMULA
a(n) = if prime(n)=4k+1 then prime(n) else prime(n)*4.
a(n) = (3*floor((prime(n) mod 4)/2) + 1)*prime(n). - Reinhard Zumkeller, Aug 20 2002
MATHEMATICA
If[Mod[#, 4]==1, #, 4#]&/@Prime[Range[60]] (* Harvey P. Dale, Jul 26 2015 *)
PROG
(PARI) a(n)=if(n<0, 0, coredisc(prime(n)))
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Aug 10 2002
STATUS
approved