

A090499


Group the natural numbers so that the sum of the numbers of divisors of the members of the (n+1)th group exceeds that for the nth group. Sequence contains the first term of each group.


2



1, 2, 3, 5, 7, 10, 13, 17, 21, 25, 30, 34, 39, 44, 49, 55, 61, 69, 77, 85, 94, 103, 113, 124, 134, 145, 157, 170, 183, 197, 211, 227, 242, 257, 273, 289, 307, 325, 344, 362, 381, 401, 421, 443, 465, 487, 511, 535, 560, 583, 607, 631, 659, 685, 713, 740, 767, 793
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


LINKS

Table of n, a(n) for n=1..58.


EXAMPLE

The groups are {1}, {2}, {3, 4}, {5, 6}, {7, 8, 9}, ... The 4th group has total d(5)+d(6) = 6. d(7)+d(8) is also 6, so 9 must be included in the 5th group to make a larger total.


CROSSREFS

Cf. A090500, A090501.
Sequence in context: A029707 A175092 A265250 * A229170 A022335 A022780
Adjacent sequences: A090496 A090497 A090498 * A090500 A090501 A090502


KEYWORD

nonn


AUTHOR

Amarnath Murthy, Dec 04 2003


EXTENSIONS

More terms from David Wasserman, Dec 08 2005


STATUS

approved



