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A111657 n-th composite number appears n-th prime times. 1
4, 4, 6, 6, 6, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

T. M. Apostol, Introduction to Analytic Number Theory, Springer-Verlag, 1976, page 2.

L. Panaitopol, Some Properties of the Series of Composed [Composite] Numbers, J. Inequalities in Pure and Applied Mathematics. 2(2): Article 38, 2000.

J. B. Rosser and L. Schoenfeld, Approximate formulas for some functions of prime numbers, Illinois J. Math. 6: 64-94 (1962).

LINKS

Table of n, a(n) for n=1..75.

Eric Weisstein's World of Mathematics, Composite Number."

Eric Weisstein's World of Mathematics, Prime Number."

FORMULA

A002808(n) appears A000040(n) times.

CROSSREFS

Cf. A000040, A002808, A111653, A111654, A111655, A111656.

Sequence in context: A019559 A274636 A198697 * A049751 A196594 A190303

Adjacent sequences:  A111654 A111655 A111656 * A111658 A111659 A111660

KEYWORD

easy,nonn

AUTHOR

Jonathan Vos Post, Aug 12 2005

STATUS

approved

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Last modified January 23 20:03 EST 2022. Contains 350515 sequences. (Running on oeis4.)