cp's OEIS Frontend

A133008 The defining property of the sequences {A, B} = {A000028, A000379} is that they are the unique pair of sets complementary with respect to the positive integers such that p(n) = |{x : x, y in A, x < y, xy = n}| = |{x : x, y in B, x < y, xy = n}| for all n >= 1. The present sequence gives the values of p(n).

%I A133008 #8 Feb 22 2013 21:38:14
%S A133008 0,0,0,0,0,1,0,1,0,1,0,1,0,1,1,0,0,1,0,1,1,1,0,0,0,1,1,1,0,0,0,1,1,1,
%T A133008 1,1,0,1,1,0,0,0,0,1,1,1,0,2,0,1,1,1,0,0,1,0,1,1,0,1,0,1,1,1,1,0,0,1,
%U A133008 1,0,0,1,0,1,1,1,1,0,0,2,0,1,0,1,1,1,1,0,0,1,1,1,1,1,1,1,0,1,1
%N A133008 The defining property of the sequences {A, B} = {A000028, A000379} is that they are the unique pair of sets complementary with respect to the positive integers such that p(n) = |{x : x, y in A, x < y, xy = n}| = |{x : x, y in B, x < y, xy = n}| for all n >= 1. The present sequence gives the values of p(n).
%H A133008 David W. Wilson, <a href="/A133008/b133008.txt">Table of n, a(n) for n = 1..10000</a>
%o A133008 (Haskell)
%o A133008 a133008 n = length [x | x <- takeWhile (< n) a000028_list,
%o A133008                     n `mod` x == 0, let y = n `div` x, x < y,
%o A133008                     y `elem` takeWhile (<= n) a000028_list]
%o A133008 -- _Reinhard Zumkeller_, Oct 05 2011
%Y A133008 Cf. A000028, A000379, A000069, A001969, A133009.
%K A133008 nonn
%O A133008 1,48
%A A133008 _David W. Wilson_, Dec 21 2007