%I A139547
%S A139547 1,2,1,6,1,1,12,2,1,1,60,2,1,1,1,60,6,2,1,1,1,420,6,2,1,1,1,1,840,12,2,
%T A139547 2,1,1,1,1,2520,12,6,2,1,1,1,1,1,2520,60,6,2,2,1,1,1,1,1,27720,60,6,2,
               2,
%U A139547 1,1,1,1,1,1,27720,60,12,6,2,2,1,1,1,1,1,1,360360,60,12,6,2,2,1,1,1,1,
               1
%N A139547 Triangle read by rows: T(n,k) = A003418(A010766).
%C A139547 This triangle fits the formula of I. Vardi in the Mathworld link about 
               the von Mangoldt function. That formula is the basis for Chebyshev's 
               estimate for the number of primes.
%D A139547 I. Vardi, Computational Recreations in Mathematica. Addison-Wesley, Redwood 
               City, CA, 1991, p. 155.
%H A139547 Weisstein, Eric W, <a href="http://mathworld.wolfram.com/MangoldtFunction.html">
               Mangoldt Function.</a>.
%e A139547 Triangle begins:
%e A139547 1;
%e A139547 2,1;
%e A139547 6,1,1;
%e A139547 12,2,1,1;
%e A139547 60,2,1,1,1;
%e A139547 60,6,2,1,1,1;
%e A139547 420,6,2,1,1,1,1;
%e A139547 840,12,2,2,1,1,1,1;
%e A139547 2520,12,6,2,1,1,1,1,1;
%e A139547 2520,60,6,2,2,1,1,1,1,1;
%e A139547 27720,60,6,2,2,1,1,1,1,1,1;
%e A139547 27720,60,12,6,2,2,1,1,1,1,1,1;
%e A139547 360360,60,12,6,2,2,1,1,1,1,1,1,1;
%e A139547 ...
%Y A139547 Cf. A000142, A010766, A014963, A003418, A139550, A139552, A139554.
%Y A139547 Sequence in context: A060480 A094673 A089808 this_sequence A126342 A082388 
               A085099
%Y A139547 Adjacent sequences: A139544 A139545 A139546 this_sequence A139548 A139549 
               A139550
%K A139547 nonn,tabl
%O A139547 0,2
%A A139547 Mats Granvik (mgranvik(AT)abo.fi), Apr 27 2008, May 07 2008
%E A139547 Edited by Mats Granvik (mats.granvik(AT)abo.fi), Jun 28 2009
%E A139547 Further edits from N. J. A. Sloane, Jul 03 2009