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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
OFFSET
1,2
COMMENTS
In the following triangle the n-th 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.
FORMULA
a(n)=A090547(n)+(n-1)*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.
Sequence in context: A139513 A144593 A057191 * A087309 A127781 A271918
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