

A073169


a(n)=A002808(n)n, difference between nth composite and n.


5



3, 4, 5, 5, 5, 6, 7, 7, 7, 8, 9, 9, 9, 10, 10, 10, 10, 10, 11, 12, 12, 12, 12, 12, 13, 13, 13, 14, 15, 15, 15, 16, 16, 16, 16, 16, 17, 17, 17, 17, 17, 18, 19, 19, 19, 19, 19, 20, 20, 20, 21, 22, 22, 22, 22, 22, 23, 23, 23, 24, 24, 24, 24, 24, 25, 25, 25, 25, 25, 25, 25, 26, 26
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OFFSET

1,1


COMMENTS

a(n) = the number of numbers of set {1, prime} (A008578(n)) less than nth composite numbers (A002808(n)). a(n) = inverse (frequency distribution) sequence of A162177(n), i.e. number of terms of sequence A162177(n) less than n for n >= 1. a(n) = A002808(n) + A162177(n)  A158611(n+1) for n >= 1. a(n) = A002808(n) + A162177(n)  A008578(n) for n >= 1. [From Jaroslav Krizek, Jul 23 2009]


LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000


FORMULA

a(n)=1+A073425(n). [From R. J. Mathar, Jul 31 2009]


MATHEMATICA

c[n_Integer] := FixedPoint[n+PrimePi[ # ]+1&, n] Table[c[w]w, {w, 1, 128}]
With[{c=Select[Range[100], CompositeQ]}, #[[1]]#[[2]]&/@Thread[ {c, Range[ Length[ c]]}]] (* Harvey P. Dale, Feb 03 2015 *)


CROSSREFS

Cf. A007821, A022449, A000040, A002808, A073168.
Sequence in context: A122816 A064007 A068568 * A166268 A239669 A185220
Adjacent sequences: A073166 A073167 A073168 * A073170 A073171 A073172


KEYWORD

nonn


AUTHOR

Labos Elemer, Jul 19 2002


EXTENSIONS

Correction for change of offset in A158611 and A008578 in Aug 2009 Jaroslav Krizek, Jan 27 2010


STATUS

approved



