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A139547 Triangle read by rows: T(n,k) = A003418(A010766). 4
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, 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, 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 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

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.

REFERENCES

I. Vardi, Computational Recreations in Mathematica. Addison-Wesley, Redwood City, CA, 1991, p. 155.

LINKS

Table of n, a(n) for n=0..88.

Weisstein, Eric W, Mangoldt Function..

EXAMPLE

Triangle begins:

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;

840,12,2,2,1,1,1,1;

2520,12,6,2,1,1,1,1,1;

2520,60,6,2,2,1,1,1,1,1;

27720,60,6,2,2,1,1,1,1,1,1;

27720,60,12,6,2,2,1,1,1,1,1,1;

360360,60,12,6,2,2,1,1,1,1,1,1,1;

...

CROSSREFS

Cf. A000142, A010766, A014963, A003418, A139550, A139552, A139554.

Sequence in context: A094673 A196839 A089808 * A126342 A229818 A082388

Adjacent sequences:  A139544 A139545 A139546 * A139548 A139549 A139550

KEYWORD

nonn,tabl

AUTHOR

Mats Granvik, Apr 27 2008, May 07 2008

EXTENSIONS

Edited by Mats Granvik, Jun 28 2009

Further edits from N. J. A. Sloane, Jul 03 2009

STATUS

approved

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Last modified October 25 17:33 EDT 2014. Contains 248557 sequences.