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A065894 Number of composites <= 10^n. 4
0, 5, 74, 831, 8770, 90407, 921501, 9335420, 94238544, 949152465, 9544947488, 95881945186, 962392087981, 9653934463160, 96795058249197, 970155429577330, 9720761658966074, 97376442842345766, 975260045712259139, 9765942332723655392, 97779180397439081159 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
Also, the order number of 10^n as a composite number.
LINKS
FORMULA
a(n) = 10^n - 1 - A006880(n). - Max Alekseyev, Aug 15 2013
For n>0, a(n) = A092871(n) + 1.
EXAMPLE
10 is the 5th composite number: 4,6,8,9,10.
MATHEMATICA
Table[ 10^n- (PrimePi[10^n]) -1, {n, 1, 13} ]
CROSSREFS
Cf. A002808.
Sequence in context: A092826 A334258 A322446 * A233013 A370463 A126740
KEYWORD
nonn
AUTHOR
Labos Elemer, Nov 28 2001
EXTENSIONS
More terms from Robert G. Wilson v, Nov 29 2001
Formula and more terms from Max Alekseyev, Aug 15 2013
STATUS
approved

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Last modified March 28 09:04 EDT 2024. Contains 371240 sequences. (Running on oeis4.)