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Search: id:A165773
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| A165773 |
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Numbers n for which phi(n) = m! for some integer m, where phi = A000010. |
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+0
4
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| 1, 2, 3, 4, 6, 7, 9, 14, 18, 35, 39, 45, 52, 56, 70, 72, 78, 84, 90, 143, 155, 175, 183, 225, 231, 244, 248, 286, 308, 310, 350, 366, 372, 396, 450, 462, 779, 793, 803, 905, 925, 1001, 1045, 1085, 1107, 1209, 1221, 1281, 1287, 1395, 1425, 1448, 1485, 1558, 1575
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OFFSET
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1,2
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COMMENT
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A subsequence of A032447. Can be read as "fuzzy" table, where the m-th row contains A055506(m) numbers with phi=m!, ranging from A055487(m) to A165774(m). See there for more information.
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EXAMPLE
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The table looks as follows:
1,2, /* A055506(1)=2 numbers for which phi(n) = 1! = 1 */
3,4,6, /* A055506(2)=3 numbers for which phi(n) = 2! = 2 */
7,9,14,18, /* A055506(3)=4 numbers for which phi(n) = 3! = 6 */
35,39,45,52,56,70,72,78,84,90, /* A055506(4)=10 numbers for which phi(n) = 4! = 24 */
143,155,175,183,225,231,244,248,286,308,310,350,366,372,396,450,462, /* A055506(5)=17 numbers for which phi(n) = 5! = 120 */ ...
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PROGRAM
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(PARI) for(m=1, 8, for( n=f=m!, f*(m+1), eulerphi(n)==f & print1(n", ")); print())
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CROSSREFS
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Sequence in context: A161890 A089388 A055494 this_sequence A064414 A002475 A057519
Adjacent sequences: A165770 A165771 A165772 this_sequence A165774 A165775 A165776
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KEYWORD
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nonn,tabf
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AUTHOR
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M. F. Hasler (MHasler(AT)univ-ag.fr), Oct 02 2009
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EXTENSIONS
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Fixed references to A055506, A055487 and A165774 M. F. Hasler (MHasler(AT)univ-ag.fr), Oct 04 2009
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