

A090548


Least number that ends an arithmetic progression of n numbers with the same number of divisors.


3



1, 3, 7, 23, 29, 157, 215, 1139, 1211, 2089, 5161, 5293, 6347, 10717, 14233, 28213, 31451, 72965, 119029, 121603, 124177, 611261, 632171, 2003171, 2012771
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OFFSET

1,2


COMMENTS

In the following triangle the nth row contains the least set of n numbers in arithmetic progression with the same number of divisors. By "least" we mean that the largest term is minimized. Sequence contains the leading diagonal. In other words, largest of n numbers in arithmetic progression with the same tau function, or 0 if no such number exists.


LINKS

Table of n, a(n) for n=1..25.


FORMULA

a(n)=A090547(n)+(n1)*A090549(n).  R. J. Mathar, Apr 28 2007


EXAMPLE

Triangle (A113470) begins:
1
2 3
3 5 7
5 11 17 23
5 11 17 23 29 ...


CROSSREFS

Leading diagonal of A113470.
Cf. A087309, A096003, A113470, A087308, A090547, A090549.
Sequence in context: A139513 A144593 A057191 * A087309 A127781 A271918
Adjacent sequences: A090545 A090546 A090547 * A090549 A090550 A090551


KEYWORD

nonn


AUTHOR

Amarnath Murthy, Dec 09 2003


EXTENSIONS

Corrected and extended by R. J. Mathar, Apr 28 2007
More terms from David Wasserman, Jan 08 2006, May 11 2007
Edited by N. J. A. Sloane at the suggestion of Andrew S. Plewe, May 11 2007


STATUS

approved



