OFFSET
0,2
FORMULA
MAPLE
A133229 := proc(n) local a016742, i, j, a ; a016742 := 4*n^2 ; a := 2*numtheory[pi](a016742) ; if n =0 then RETURN(-1) ; fi ; for i from 1 to numtheory[pi](a016742-1) do if isprime(a016742-ithprime(i)) then j := numtheory[pi](a016742-ithprime(i)) : a := min(a, i+j) ; fi ; od: RETURN(a) ; end: seq(A133229(n), n=0..80) ; # R. J. Mathar, Apr 22 2008
MATHEMATICA
Join[{-1}, Table[Min[Total/@(PrimePi/@Select[IntegerPartitions[4 n^2, {2}], AllTrue[ #, PrimeQ]&])], {n, 70}]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 18 2021 *)
CROSSREFS
KEYWORD
sign
AUTHOR
Alexander R. Povolotsky, Dec 19 2007
EXTENSIONS
Edited and extended by R. J. Mathar, Apr 22 2008
STATUS
approved