A202177 Number of partitions p of n such that each part of p is prime and each part of the conjugate partition of p is also prime.
0, 0, 0, 1, 0, 2, 0, 1, 1, 2, 0, 2, 2, 2, 2, 3, 3, 0, 4, 2, 5, 2, 4, 3, 8, 2, 6, 4, 11, 0, 10, 4, 14, 2, 14, 4, 21, 2, 20, 5, 25, 0, 28, 6, 30, 2, 38, 5, 46, 0, 44, 4, 54, 0, 56, 6, 67, 2, 72, 4, 93, 2, 74, 7, 113, 0, 100, 8, 131, 0, 128
Offset: 1
Keywords
Examples
For n=17, there are three valid partitions: (7,7,3), its conjugate partition (3,3,3,2,2,2,2), and the self-conjugate partition (5,5,3,2,2). Thus a(17)=3.
Links
- Eric Weisstein's World of Mathematics, Prime Partition.
Programs
-
Mathematica
ConjugatePartition[l_List] := Module[{i, r = Reverse[l], n = Length[l]}, Table[n + 1 - Position[r, _?(# >= i &), Infinity, 1][[1, 1]], {i, l[[1]]}]];f[n_] := Select[Select[IntegerPartitions[n], And @@ (PrimeQ[#]) &], And @@ (PrimeQ[ConjugatePartition[#]]) &];a[n_] := Length[f[n]];Table[a[n],{n,1,40}]