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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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