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A325129
Heinz numbers of integer partitions into nonsquares (A087153).
2
1, 3, 5, 9, 11, 13, 15, 17, 19, 25, 27, 29, 31, 33, 37, 39, 41, 43, 45, 47, 51, 55, 57, 59, 61, 65, 67, 71, 73, 75, 79, 81, 83, 85, 87, 89, 93, 95, 99, 101, 103, 107, 109, 111, 113, 117, 121, 123, 125, 127, 129, 131, 135, 137, 139, 141, 143, 145, 149, 153, 155
OFFSET
1,2
COMMENTS
The Heinz number of an integer partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k).
EXAMPLE
The sequence of terms together with their prime indices begins:
1: {}
3: {2}
5: {3}
9: {2,2}
11: {5}
13: {6}
15: {2,3}
17: {7}
19: {8}
25: {3,3}
27: {2,2,2}
29: {10}
31: {11}
33: {2,5}
37: {12}
39: {2,6}
41: {13}
43: {14}
45: {2,2,3}
MATHEMATICA
Select[Range[100], !MemberQ[If[#==1, {}, FactorInteger[#]], {p_, _}/; IntegerQ[Sqrt[PrimePi[p]]]]&]
KEYWORD
nonn
AUTHOR
Gus Wiseman, Apr 01 2019
STATUS
approved