A036335 Total number of composite numbers with n digits and n prime factors (counted with multiplicity).

0, 31, 225, 1563, 10222, 63030, 374264, 2160300, 12196405, 67724342, 371233523, 2014305995

Offset

1,2

Comments

Essentially the same as A124033.

Links

Table of n, a(n) for n=1..12.

Carlos Rivera, Puzzle 25. Composed primes (by G.L. Honaker, Jr.), The Prime Puzzles and Problems Connection. (A related puzzle.)

Example

a(1) = 0, since any single-digit number with 1 prime factor is a prime!

Mathematica

Table[Total[Table[If[CompositeQ[n]&&PrimeOmega[n]==x, 1, 0], {n, 10^(x-1), 10^x-1}]], {x, 8}] (* The program generates the first 8 terms of the sequence. *) (* Harvey P. Dale, Jun 19 2022 *)

Crossrefs

Cf. A036336, A036337, A036338.

Sequence in context: A256172 A142939 A229018 * A075931 A142440 A075932

Adjacent sequences: A036332 A036333 A036334 * A036336 A036337 A036338

Keyword

nonn,base,more

Author

Patrick De Geest, Dec 15 1998

Extensions

One more term from Naohiro Nomoto, Jul 31 2001

a(9)-a(12) from Ray Chandler, Apr 12 2011

Status

approved