A065894 Number of composites <= 10^n.

0, 5, 74, 831, 8770, 90407, 921501, 9335420, 94238544, 949152465, 9544947488, 95881945186, 962392087981, 9653934463160, 96795058249197, 970155429577330, 9720761658966074, 97376442842345766, 975260045712259139, 9765942332723655392, 97779180397439081159

Offset

0,2

Comments

Also, the order number of 10^n as a composite number.

Links

Amiram Eldar, Table of n, a(n) for n = 0..29 (calculated using the b-file at A006880)

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, A006880, A092871.

Sequence in context: A375220 A334258 A322446 * A233013 A370463 A126740

Adjacent sequences: A065891 A065892 A065893 * A065895 A065896 A065897

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