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A325511
Numbers whose prime signature is that of a factorial number.
2
1, 2, 3, 5, 6, 7, 10, 11, 13, 14, 15, 17, 19, 21, 22, 23, 24, 26, 29, 31, 33, 34, 35, 37, 38, 39, 40, 41, 43, 46, 47, 51, 53, 54, 55, 56, 57, 58, 59, 61, 62, 65, 67, 69, 71, 73, 74, 77, 79, 82, 83, 85, 86, 87, 88, 89, 91, 93, 94, 95, 97, 101, 103, 104, 106
OFFSET
1,2
COMMENTS
A181819(a(n)) belongs to A325508.
EXAMPLE
The sequence of terms together with their prime indices begins:
1: {}
2: {1}
3: {2}
5: {3}
6: {1,2}
7: {4}
10: {1,3}
11: {5}
13: {6}
14: {1,4}
15: {2,3}
17: {7}
19: {8}
21: {2,4}
22: {1,5}
23: {9}
24: {1,1,1,2}
26: {1,6}
29: {10}
31: {11}
MATHEMATICA
Select[Range[30], MemberQ[Table[Sort[Last/@FactorInteger[k!]], {k, #}], Sort[Last/@FactorInteger[#]]]&]
KEYWORD
nonn
AUTHOR
Gus Wiseman, May 08 2019
STATUS
approved