OFFSET
1,7
FORMULA
a(n) = Sum_{i=1..floor((n-1)/2)} [Omega(n-i) = 2] * (1-[Omega(n-2*i) = 2]), where [] is the Iverson bracket and Omega = A001222.
MATHEMATICA
Table[Sum[KroneckerDelta[PrimeOmega[n - i], 2] (1 - KroneckerDelta[PrimeOmega[n - 2 i], 2]), {i, Floor[(n - 1)/2]}], {n, 100}]
Table[Count[IntegerPartitions[n, {2}], _?(PrimeOmega[#[[1]]]==2 && PrimeOmega[ #[[1]]-#[[2]]]!=2&)], {n, 100}] (* Harvey P. Dale, Jun 30 2021 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wesley Ivan Hurt, Apr 18 2018
STATUS
approved