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.

A122376 Number of prime factors (counted with multiplicity) of the smallest number with exactly n divisors.

This page as a plain text file.
%I A122376 #27 Dec 11 2021 04:57:18
%S A122376 0,1,2,2,4,3,6,4,4,5,10,4,12,7,6,5,16,5,18,6,8,11,22,6,8,13,6,8,28,7,
%T A122376 30,6,12,17,10,6,36,19,14,7,40,9,42,12,8,23,46,7,12,9,18,14,52,7,14,9,
%U A122376 20,29,58,8,60,31,10,8,16,13,66,18,24,11,70,9,72,37,10,20,16,15,78,9,8,41
%N A122376 Number of prime factors (counted with multiplicity) of the smallest number with exactly n divisors.
%C A122376 This function is not additive; the smallest counterexample is a(40) = 7 != 4 + 4 = a(5) + a(8). - _Franklin T. Adams-Watters_ Jul 10 2009
%H A122376 David A. Corneth, <a href="/A122376/b122376.txt">Table of n, a(n) for n = 1..10000</a> (first 2000 terms from Amiram Eldar)
%F A122376 a(n) = Omega(A005179(n)), where Omega(n) = A001222(n).
%F A122376 a(p) = p-1 for prime p.
%F A122376 a(n) = A001222(A130279(n))/2. - _Reinhard Zumkeller_, May 21 2007
%t A122376 s = { (* terms in A005179 *) }; f[n_] := Plus @@ Last /@ FactorInteger@n; f /@ s (* _Robert G. Wilson v_, Aug 31 2006 *)
%Y A122376 Cf. A001222, A005179, A130279.
%K A122376 nonn
%O A122376 1,3
%A A122376 _Lekraj Beedassy_, Aug 30 2006
%E A122376 More terms from _Robert G. Wilson v_, Aug 31 2006
%E A122376 Edited and extended by _Ray Chandler_, Sep 11 2006
%E A122376 Incorrect comment removed by _Franklin T. Adams-Watters_, Jul 11 2009