cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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

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%I A036335 #16 Jun 19 2022 12:52:41
%S A036335 0,31,225,1563,10222,63030,374264,2160300,12196405,67724342,371233523,
%T A036335 2014305995
%N A036335 Total number of composite numbers with n digits and n prime factors (counted with multiplicity).
%C A036335 Essentially the same as A124033.
%H A036335 Carlos Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_025.htm">Puzzle 25. Composed primes (by G.L. Honaker, Jr.)</a>, The Prime Puzzles and Problems Connection. (A related puzzle.)
%e A036335 a(1) = 0, since any single-digit number with 1 prime factor is a prime!
%t A036335 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 *)
%Y A036335 Cf. A036336, A036337, A036338.
%K A036335 nonn,base,more
%O A036335 1,2
%A A036335 _Patrick De Geest_, Dec 15 1998
%E A036335 One more term from _Naohiro Nomoto_, Jul 31 2001
%E A036335 a(9)-a(12) from _Ray Chandler_, Apr 12 2011