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Search: id:A070296
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| A070296 |
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Let sphi(k) = number of primes less than k and coprime to it (A048865); then a(n) = number of integers m with sphi(m) = n. |
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2
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| 2, 3, 2, 4, 3, 3, 4, 5, 3, 5, 6, 1, 4, 5, 8, 2, 5, 4, 3, 5, 4, 7, 7, 5, 2, 3, 3, 6, 10, 5, 7, 2, 10, 3, 4, 7, 5, 4, 7, 4, 7, 3, 5, 2, 12, 10, 5, 3, 4, 5, 2, 10, 6, 7, 5, 3, 5, 4, 4, 9, 14, 3, 3, 5, 12, 8, 7, 3, 5, 7, 6, 7, 5, 5, 6, 7, 6, 9, 7, 4, 7, 5, 5, 3, 8, 7, 3, 2, 7, 10, 7, 7, 4, 7, 7
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OFFSET
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0,1
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FORMULA
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a(n) = number of m such that A048865(m) = n.
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EXAMPLE
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a(4) = 3. The three values of m for which sphi(m) = 4 are 11, 14 and 15. The coprime primes less than 11 are 2, 3, 5, and 7. The coprime primes less than 14 are 3, 5, 11, and 13. The coprime primes less than 15 are 2, 7, 11, and 13.
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MATHEMATICA
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(continuing from A048865) Table[Count[t, i], {i, 0, 150}]
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CROSSREFS
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Sequence in context: A105117 A100876 A089215 this_sequence A072645 A135817 A122060
Adjacent sequences: A070293 A070294 A070295 this_sequence A070297 A070298 A070299
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), May 10 2002
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EXTENSIONS
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More terms from Hans Havermann (pxp(AT)rogers.com), Jun 04, 2002
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