OFFSET
1,16
MATHEMATICA
Table[Sum[(PrimePi[i] - PrimePi[i - 1]) (PrimePi[n - i] - PrimePi[n - i - 1]) MoebiusMu[n - 2 i]^2, {i, Floor[(n - 1)/2]}], {n, 100}]
Table[Count[IntegerPartitions[n, {2}], _?(AllTrue[#, PrimeQ]&&SquareFreeQ[#[[1]]-#[[2]]]&)], {n, 100}] (* Harvey P. Dale, Aug 05 2023 *)
PROG
(PARI) a(n) = sum(i=1, (n-1)\2, isprime(i)*isprime(n-i)*issquarefree(n-2*i)); \\ Michel Marcus, Apr 21 2018; corrected by Jun 14 2022
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wesley Ivan Hurt, Apr 19 2018
STATUS
approved