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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
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 May 29 03:48 EDT 2024. Contains 372921 sequences. (Running on oeis4.)