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A158907 Row sums of triangle A158906.

%I A158907 #35 Dec 26 2020 03:31:21
%S A158907 1,3,4,6,6,9,8,11,11,13,12,17,14,17,18,20,18,23,20,25,24,25,24,31,27,
%T A158907 29,30,33,30,37,32,37,36,37,38,44,38,41,42,47,42,49,44,49,50,49,48,57,
%U A158907 51,55,54,57,54,61,58,63,60,61,60
%N A158907 Row sums of triangle A158906.
%C A158907 This is the number of pairs of positive integers (i,j) such that i*j = n or i+j = n (where (2,2) is double-counted as both 2+2=4 and 2*2=4.) - _Peter Kagey_, Oct 02 2020
%F A158907 a(n) = Sum_{k=1..n} A158906(n,k).
%F A158907 a(p) = p + 1 for prime p. [corrected by _Ruediger Jehn_, Dec 25 2020]
%F A158907 a(n) = A032741(n) + n. - _R. J. Mathar_, Jan 08 2015
%F A158907 a(n) = Sum_{i=1..n} floor(n/i)-floor((n-1)/(i+1)). - _Wesley Ivan Hurt_, Sep 13 2017
%e A158907 a(4) = 6 = (4 + 1 + 0 + 1).
%p A158907 A158906 := proc(n,k)
%p A158907     add( A158821(n-1,j-1)*A051731(j,k),j=k..n) ;
%p A158907 end proc:
%p A158907 A158907 := proc(n)
%p A158907     add(A158906(n,k),k=1..n) ;
%p A158907 end proc:
%p A158907 seq(A158907(n),n=1..62) ; # _R. J. Mathar_, Jan 08 2015
%Y A158907 Cf. A032741, A158906.
%K A158907 nonn,easy
%O A158907 1,2
%A A158907 _Gary W. Adamson_ and _Mats Granvik_, Mar 29 2009