OFFSET
1,9
LINKS
J. Stauduhar, Table of n, a(n) for n = 1..10000
EXAMPLE
For n = 6, in the set {{5, 1}, {4, 2}, {3, 3}}, {4, 2} is the only partition that satisfies the requirements, so a(6) = 1.
For n = 9, we have partitions {6, 3} and {5, 4}, so a(9) = 2.
MATHEMATICA
Table[Length[Select[Range[2, Floor[n/2]], (PrimeQ[#] && Not[PrimeQ[n - #]]) || (Not[PrimeQ[#]] && PrimeQ[n - #]) &]], {n, 80}] (* Alonso del Arte, Apr 21 2013 *)
Table[Count[IntegerPartitions[n, {2}], _?(FreeQ[#, 1]&&Total[Boole[ PrimeQ[ #]]] == 1&)], {n, 80}] (* Harvey P. Dale, Jul 21 2021 *)
PROG
(PARI) a(n)=my(s); forprime(p=2, n-4, s+=!isprime(n-p)); s \\ Charles R Greathouse IV, Apr 30 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
J. Stauduhar, Apr 20 2013
STATUS
approved