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 n-th group. Sequence contains the first term of each group.

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

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