A090548 - OEIS

A090548

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

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 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.

LINKS

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

FORMULA

a(n)=A090547(n)+(n-1)*A090549(n). - R. J. Mathar, Apr 28 2007

EXAMPLE

Triangle (A113470) begins:

2 3

3 5 7

5 11 17 23

5 11 17 23 29 ...

CROSSREFS

Leading diagonal of A113470.