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 A070296 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. 1
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 LINKS FORMULA a(n) = number of m such that A048865(m) = n. EXAMPLE 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. MATHEMATICA (continuing from A048865) Table[Count[t, i], {i, 0, 150}] CROSSREFS Sequence in context: A318046 A246348 A205782 * A303581 A216647 A072645 Adjacent sequences:  A070293 A070294 A070295 * A070297 A070298 A070299 KEYWORD nonn AUTHOR Amarnath Murthy, May 10 2002 EXTENSIONS More terms from Hans Havermann, Jun 04, 2002 STATUS approved

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Last modified March 24 19:39 EDT 2019. Contains 321448 sequences. (Running on oeis4.)