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A073169 a(n)=A002808(n)-n, difference between n-th 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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
a(n) = the number of numbers of set {1, prime} (A008578(n)) less than n-th 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
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
Sequence in context: A064007 A358127 A068568 * A166268 A239669 A185220
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

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Last modified February 27 23:21 EST 2024. Contains 370379 sequences. (Running on oeis4.)