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A320325 Numbers whose product of prime indices is a perfect power. 24
7, 9, 14, 18, 19, 21, 23, 25, 27, 28, 36, 38, 42, 46, 49, 50, 53, 54, 56, 57, 63, 72, 76, 81, 84, 92, 97, 98, 100, 103, 106, 108, 112, 114, 115, 121, 125, 126, 131, 133, 144, 147, 151, 152, 159, 161, 162, 168, 169, 171, 175, 183, 184, 185, 189, 194, 195, 196 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798.
LINKS
EXAMPLE
The terms together with their corresponding multiset multisystems (A302242):
7: {{1,1}}
9: {{1},{1}}
14: {{},{1,1}}
18: {{},{1},{1}}
19: {{1,1,1}}
21: {{1},{1,1}}
23: {{2,2}}
25: {{2},{2}}
27: {{1},{1},{1}}
28: {{},{},{1,1}}
36: {{},{},{1},{1}}
38: {{},{1,1,1}}
42: {{},{1},{1,1}}
46: {{},{2,2}}
49: {{1,1},{1,1}}
50: {{},{2},{2}}
53: {{1,1,1,1}}
54: {{},{1},{1},{1}}
56: {{},{},{},{1,1}}
57: {{1},{1,1,1}}
63: {{1},{1},{1,1}}
72: {{},{},{},{1},{1}}
76: {{},{},{1,1,1}}
81: {{1},{1},{1},{1}}
MATHEMATICA
Select[Range[100], GCD@@FactorInteger[Times@@Cases[FactorInteger[#], {p_, k_}:>PrimePi[p]^k]][[All, 2]]>1&]
CROSSREFS
Sequence in context: A145827 A116025 A344011 * A320699 A332514 A353168
KEYWORD
nonn
AUTHOR
Gus Wiseman, Oct 10 2018
STATUS
approved

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Last modified March 19 07:40 EDT 2024. Contains 370958 sequences. (Running on oeis4.)